Transitional fossils are those fossils WHICH HAVE FEATURES THAT ARE INTERMEDIATE BETWEEN ANCESTORS AND DESCENDANTS. This type of fossils have characteristics traits that are common to both an ancestral group and its derived descendant group.
Reverse faults are exactly the opposite of normal faults. If the hanging wall rises relative to the footwall you have a reverse fault. Reverse faults occur in areas undergoing compression. If you imagine undoing the motion of a reverse fault, you will undo the compression and thus lengthen the horizontal distance between two points on either side of the fault.
if you stood on the fault plane the block on the right would be under your feet. this is thus the footwall. The tan sandstone has been pushed up and over itself. This offset of the hanging wall indicates that this is a reverse fault.
they are caused by mutation. the best example of it are human blood groups.
I am sure that the answer is D