Identify the segment in the sentence, which contains the grammatical error.
Each student will have to carry his own lunch on the picnic.

Correct option is C

The error is in segment (c), "on the picnic." The correct preposition should be "to the picnic" instead of "on the picnic." When talking about attending or bringing something to an event, we use the preposition "to."
Grammatical rule used: The preposition "to" is used to indicate direction or movement toward a specific destination or event.
Example:
· Incorrect: She brought snacks on the party.
· Correct: She brought snacks to the party.
Thus, the correct sentence should be: "Each student will have to carry his own lunch to the picnic."