About ____________ the first cellular forms of life appeared on earth.

The correct answer is Option (3) → 2000 million years ago

The story of life on earth runs on a long time scale. The earth was formed about 4.5 billion years ago, and life appeared about 500 million years after that, close to 4 billion years ago. For a long time this life was non-cellular. The first cellular forms appeared about 2000 million years ago, and some of these cells later began to release oxygen.

NCERT Extract:
A Brief Account of Evolution – …