help
I can help you choose your answer. The examiner appears to subscribe to a commonly held view that sfc varies as the ratio of N1 divided by the square root of absolute temperature at the compressor stator outlet. The examiner appears to me at least to be doing his best to suggest that everything else remains constant besides N1. Therefore if his premise is correct, at least within the confines of the exam, sfc varies inversely with the square root of absolute temperature only. If only someone had told the engines to always react with such simplicity!
Good Luck and always remember the examiner is correct, regardless...