In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'.
Mother does not hardly(A)/know what happened(B)/in school yesterday. (C)/No error(D)

Part (A) contains an error due to the usage of a double negative.
The word "hardly" is a negative adverb meaning 'scarcely' or 'almost not'. Using "does not" along with "hardly" creates an ungrammatical double negative statement.

The correct sentence structure should be: "Mother hardly knows what happened..." or "Mother does not know what happened..."