Fill in the blank with the most suitable word.
A haze of panic blurred my vision; something terrible was close to ______.

Correct option is D

The correct option to fill in the blank is (d) happening.
The phrase “close to” is followed by a gerund (verb+ing) to indicate something that is about to occur. Hence, "happening" is the correct form here.
Example: The team was close to winning the game.
Explain why other options are incorrect:
· (a) has happened – Present perfect, not used with "close to"
· (b) happened – Simple past, not fitting with ongoing context
· (c) happens – Present simple, incorrect structure here
Information Booster: After prepositions like "to", use the gerund (V+ing) form of verbs when expressing ongoing/future events.