Explanation:

• It is used in spraying pasticides and inspecting volcanoes also. The SnotBot is in fact a drone adapted for sampling whale breath that films while capturing the precious mucus in four Petri dishes or on sponges. To date, analyses have been used to identify DNA, ketones, hormones (notably to determine whether the animal is pregnant) and microbiomes contained in the whale exhalations.
• Recently, Scientists flew a small drone over the blowhole of a few humpback whales in the US and Canada to collect the microbes living inside their breath. Sampling the community of microbes and bacteria living inside whales, called the microbiome, can help us better understand what makes a healthy whale, and what happens when a whale gets sick.

Hence option 4th is correct.

For More: https://www.theverge.com/2017/10/13/16468698/drone-humpback-whale-microbiome-health-conservation