Which words are the first and last words of the gerund phrase in this sentence? Do not delay reporting any malfunction to the representative. A. do delay B. do reporting C. reporting malfunction D. reporting representative

So are they asking for which words would be good for "Do bot delay reporting any malfunction to the representative"? And what i mean is like switch it out with something in the sentence that dosent make sense because if so i would pick C or D but mostly D