To determine the system that could potentially explain the voter-seat distortion in the election results, let`s analyze the given table:

Political Party | Percentage of Popular Votes Obtained | Number of Seats Secured

----------------|-------------------------------------|-----------------------

Janata Dal | 3.6 | 1.16

Congress | 3.1 | 3.5

BJP | 2.04 | 4.0

Option 1: Hare System

The Hare system, also known as the Single Transferable Vote (STV) system, is a proportional representation system where voters rank candidates in order of preference. It allows for the transfer of votes from candidates who exceed the minimum threshold required to win a seat. The Hare system tends to produce a proportional distribution of seats based on the percentage of votes obtained.

Looking at the table, we observe that the seat distribution does not closely align with the percentage of popular votes obtained by each party. The Janata Dal received 3.6% of the votes but only secured 1.16 seats, while the Congress received 3.1% of the votes but secured 3.5 seats. These disparities suggest that the Hare system is not the adopted system in this scenario.

Option 2: Cumulative Vote System

The Cumulative Vote system allows voters to allocate multiple votes to a single candidate or distribute their votes across different candidates. This system is often used in multi-member districts, and the seats are allocated based on the total number of votes received by each candidate.

The given table does not provide any information about the number of votes cast by individual voters or the distribution of votes. Therefore, we cannot conclusively determine if the Cumulative Vote system was adopted or not.

Option 3: First-past-the-post System

The First-past-the-post (FPTP) system, also known as the winner-takes-all system, is a simple plurality system where the candidate with the most votes in a constituency wins the seat. This system does not necessarily lead to proportional representation and can result in voter-seat distortions.

Given the information in the table, the seat distribution seems to align more closely with the percentage of popular votes obtained by each party. The BJP received 20.4% of the votes and secured 4 seats, while the Congress received 31% of the votes and secured 3.5 seats. This suggests that the First-past-the-post system could be the adopted system in this scenario.

Option 4: Plural Vote System

The Plural Vote system is a historical electoral system where certain individuals, based on their social or economic status, were granted multiple votes. This system is no longer widely used and is unlikely to be the adopted system in this case.

Considering the information provided and the disparities between the percentage of popular votes obtained and the number of seats secured by each party, the most plausible explanation is that the election results are the outcome of the First-past-the-post (FPTP) system. However, without additional information about the voting system used and specific rules in place, it is difficult to make a definitive determination.