I see her (a)/ most weekends (b)/ but not very often between . ©/ No error (d)

Read each sentence to find out whether there is any grammatical or idiomatic error in it. The error, if any, will be in one part of the sentence. Mark the letter of that part as your answer. If there is no error, mark ( e ) as your answer. Science students can (a)/ attend their classes (b))/ on weekend and (c)/ working during the week. (d)/ No error (e).