Select the correctly spelt word to fill in the blank.
Helium is used with oxygen for asthma treatment because it ____________ very easily.

Correct option is C

The correct spelling to fill in the blank is diffuses, which means to spread or cause to spread over a wide area or among a large number of people (फैलना).
· Example: The pleasant aroma diffuses throughout the room.
Meanings of other given options and why they are incorrect:
· Difusez: Incorrect spelling, no such word exists.
· Difuses: Incorrect spelling, missing an additional "f".
· Diffuzes: Incorrect spelling, "z" is used instead of "s".