The correct answer is option-1, Circum-Atlantic Ocean.

Seismic activity refers to the occurrence of earthquakes and the resulting ground shaking. The other three options, Circum-Pacific Ocean, Circum-Indian Ocean, and Mid-Atlantic Ocean, are all areas known for their high seismic activity.

1. Circum-Atlantic Ocean: This option is not an area of seismic activity. The Atlantic Ocean is generally considered to have fewer earthquakes compared to other ocean regions. While there may be some seismic activity in certain regions of the Atlantic Ocean, it is not as frequent or intense as in the other options.

2. Circum-Pacific Ocean: Also known as the Ring of Fire, this region is highly active in terms of seismic activity. It is characterized by frequent earthquakes and volcanic eruptions due to tectonic plate boundaries and subduction zones.

3. Circum-Indian Ocean: This region is also prone to seismic activity due to tectonic plate boundaries, particularly around the Indian subcontinent and the surrounding oceanic plates.

4. Mid-Atlantic Ocean: This region is an area of moderate seismic activity. It is characterized by seismic activity along the Mid-Atlantic Ridge, which is a divergent plate boundary where new crust is formed.

Overall, while