3. Which of the following statements is/are correct?

i. The flame of a Bunsen burner is blue when the air hole is open and yellow when the air hole is closed.
ii. The liquid or solid wax never catches fire of its own.
iii. A substance cannot catch fire if its temperature is higher than its ignition temperature.
iv. Water should be poured over burning petrol, kerosene, or diesel.
v. The middle zone of a candle emits the least light.

a. i and ii only
b. iii and iv only
c. ii, iii, and iv only
d. v only