Fill in the blank with the most appropriate word.
Turn the T.V off. No one __________ it!
a) Watches
b) Watch
c) Is watching
d) Watched

Hint: Here, the speaker is clearly indicating that no one is watching the T.V. hence it should be closed. To watch something means to ‘see’.

Complete answer:
Before answering the question let us look into the option and understand their meaning and usage.
Option (a) – ‘watches’: watches is the third-person singular simple present indicative form of the word watch. For example he watches a lot of television series.
Option (b) – ‘watch’: watch is the root word which means to see. For example I used to watch you while you played here.
Option (c) – ‘is watching’: watching is the present participle form of a watch. Is watching indicates that someone is watching it presently. For example, no one is watching it.
Option (d) – ‘watched’: watched is the past tense (simple and past participle tense) of the word watch. For example he watched the game.
So, since we need the present participle tense to complete the sentence, so as to indicate that no one is watching (or has been watching for a while) in the present time.
Hence, as per the explanation given above the correct solution would be the option given in option (c), i.e. is watching.
This completes the sentence as – ‘Turn the T.V. off. No one is watching it!’.

Note:
In the question, we need the present participle form of the word watch to complete the sentence as the function of the present participle is to serve as an adjective, a verb or a gerund.