Please choose the correct one from the set of possible answers to this question.

It's very exciting to see a crowd of horses running at the racetrack.

A new approach is needed to solve this set of problems.

This colony is forming a unique ecosystem.

A meteor shower appeared in the night sky.

Suddenly, a rainfall that starts and stops abruptly began and then stopped immediately.

We offer a wide range of product lines to meet our customers' needs.

He is suffering from Raynaud's syndrome.

We analyzed the data of the experimental group.

He is studying the major ethnic groups in that region.