Question

My father will return home ________ the evening.
a. on
b. at
c. in
d. to​

Answer 1

My father will return home in the evening.

• The given options are examples of prepositions of time.
• 'In' is used to refer to parts of days, that is, in the morning, in the afternoon etc. It is also employed to express general time like months, centuries, etc
• 'On' is used for specific days, like, on Wednesday, or a particular date, like, on 2nd March.
• 'At' is used to refer to a specific time, like, at 10 AM.  

Answer 2

My father will return home in the evening.

• "In" is the correct preposition in the given sentence.

• A preposition is a word that is used to link nouns, pronouns to other words in a given sentence.

• A preposition usually precedes a noun or pronoun and expressing a relation to another word.

• These are small words but they are the most important ones. A preposition sits in front of its object.