Indeed. It is a complete sentence, since there is no slang or incorrect grammar in this sentence.
I honestly think that the answer is A, but I might be wrong. Just to be safe, you may want to check with someone else. Hope this helps.
Probably C. It’s the only one that makes sense.
Answer:
Go on the ELA version they have all the answers including this one. Im sorry i couldnt answer but hopefully this works. Someone just told me this Yesterday and it helped a lot.
Explanation: