Beena, Shalu and Navpreet wanted to find out who among them had the biggest lung capacity. They decided to blow into a balloon with one breath and see how big it will become. Which of the following factors they must keep the same to make the test a fair one?
1. Colour and design pattern of the balloon
2. Size and shape of the balloon
3. When to breathe in forcibly before blowing
4. Material, balloon is made of
A 1 and 2 only
B 2 and 3 only
C 1, 3 and 4 only
D 2, 3 and 4 only
The answer is D