A. Possibly. It is possible that her dates are wrong and that she is only 13 weeks pregnant but she reports a normal menstrual cycle and she was sure of her dates.
B. Possibly. A baby with a very small head is a very rare abnormality.
C. Unlikely. The measurement end points appear to be correctly positioned although it is difficult to see normal internal anatomy of the fetal brain.
D. Most likely. The dates are sure and the head much too small, implying absent growth over several weeks and probably collapse of the skull bones. In this situation, sometimes the skull bones can overlap.