In option (a), the verb 'takes' which is in third person singular form (V5) follows the modal verb 'will' which is incorrect, as modals verb are to be followed by verbs in base form alone (V1). So, 'takes' must be replaced by 'take'.
In option (b), the 'be' form of the verb is to be in the past participle form (V3) to match the past perfect tense of the sentence (Subject+ had+ been+ verb+ object). Instead, the 'be' form of verb is in base form (V1) and it must be replaced by 'been'.
In option (d), the verb 'comes' corresponds to a singular noun, but the noun 'people' is plural and so the plural form of the verb is to be used. In the place of 'comes', 'come' is to be used.
Option (c), is the sentence that is grammatically and contextually correct without any errors.
Hence, the correct answer is option (c).
Note:
V1 -> Base form/simple form of verb, V2 -> Past form of verb (-ed form or irregular verb), V3 -> Past participle form of verb (-ed, -d, -t, -en, or -n), V4 -> Continuous form of verb / Present participle form of verb (-ing form), V5 -> Third person singular (V1+ -es or -s).
Modal verb: A verb used with another verb to express an idea such as possibility that is not expressed by the main verb. The modal verbs in English are "can," "could," "may," "might," "must," "ought," "shall," "should," "will," and "would." They do not change their form (spelling) and they have no infinitive or participle (past/present). Example: I can speak Spanish. Here 'can' expresses the ability of the person to speak (main verb) Spanish. This ability cannot be expressed by the main verb 'speak'.
Tense: Grammatical tense tells us or expresses the time period that the action happens in. It can be happening now (present) or has happened already (past) or will happen later (future). Tenses help us understand how to use verbs correctly to indicate when the action took place.