At first, it was fine. I found that when the image was rotated 90 degrees about G, every point and line segment ended up in the position of another line point on the preimage. Sorry if that sounds confusing, but for example segment EB ended up right on top of segment MJ, and therefore I put MJ as my answer.
However, when I got to C, I started having problems. When the shape is rotated about M, none of the points or segments of the image match any of the segments in the pre-image (except for M).
I didn't know what to answer, as to me, the only way to name the segment is segment segment I'M', but that doesn't really tell you anything, besides that the image has been transformed.
What am I missing, and is there an error in the way I answered A and B???
I think you are mixing up 'clockwise' and 'counterclockwise' directions. $EB$ ends up on top of $MJ$ for a counterclockwise rotation, not a clockwise one. I assume you are making the same mistake for part (c), because a clockwise rotation results in a line segment that does not match any of the existing ones, as you are describing.