The correct answer is: E. No error
The sentence is grammatically correct. The verb “expect” takes a singular subject, so “Mihir expects” is correct. The preposition “to” is used to indicate the purpose of the action, so “to meet him” is correct. The adverb “once in a week” indicates the frequency of the action, so it is also correct.
The other options are incorrect because they would make the sentence grammatically incorrect. Option A is incorrect because it does not include the verb “told.” Option B is incorrect because it uses the plural verb “expect” with the singular subject “Mihir.” Option C is incorrect because it does not include the preposition “to.” Option D is incorrect because it does not include the adverb “once in a week.”