The Speaker of the First Lok Sabha was G.V. Mavalankar. Each option represents a notable figure, so let`s explore who they were:

Option 1: Hukam Singh was the Speaker of the Lok Sabha from 1962 to 1967 (third and fourth Lok Sabha), not the first.

Option 2: G.V. Mavalankar was indeed the Speaker of the First Lok Sabha, serving from 1952 to 1956. He was also the first Speaker of independent India`s provisional parliament before the first Lok Sabha election.

Option 3: K.M. Munshi was a prominent lawyer, writer, and statesman who made significant contributions to the early years of India`s independence, but he was never a Lok Sabha Speaker.

Option 4: U.N. Dhebar was the President of the Indian National Congress from 1955 to 1959, but he was not a Lok Sabha Speaker.

Hence, the correct answer is indeed G.V. Mavalankar (Option 2).