Onein60rule.
I made no mistake in question 27.
The question asks about SFC. SFC is a measure of how much fuel is required per hour to produce each unit of thrust. SFC depends upon RPM and ambient temperature. It is not affected by C of G position, provided the RPM is not changed sufficiently to require the engines to be moved out of the optimum 85% to 95% RPM range.
Even if we assume that RPM does need to change that much, SFC will increase only if we were already in the optimum RPM range prior to the C of G change and the C of G change caused us to move out of that optimum range. I believe that this question is actually probing the student's knowledge of the difference between SFC and specific Range.
A number of schools have previously taught that C of G affects SFC. Most have now amended their teaching, but some have not. I believe that they are wrong.
I suspect that you are confusing this with question 20, refers to " fuel consumption in ANM/Kg". These unit refer to Specific Range not SFC. It is however true that forward movement of the C of G would reduce specific range and increase gross fuel consumption.