Improve the bracketed part of the sentence. If there is no improvement, then select 'No improvement'.
It is high time that civilians (awake to) the dangers surrounding them.

Correct option is D

The correct substitution of the bracketed words is (d) wake up to.
Explanation:
The expression “It is high time that...” is always followed by the simple past tense or a subjunctive base form to express urgency or necessity.
The correct verb is “wake up to”, meaning become aware of or conscious of.
Grammatical rule used:
After "It is high time that", we use the bare infinitive/base form (subjunctive mood) in formal English.
Example:
· It is high time we took action.
· It is high time you learn discipline.
Why other options are incorrect:
· (a) “awake to” → incorrect tense and unidiomatic
· (b) “awakens to” → wrong subject-verb agreement
· (c) “awakens on” → incorrect preposition