A. The difference between "pitiful" and "piteous" is in the connotation. Both words can mean deserving pity, but "pitiful" also has the connotation of contempt: "It was a pitiful attempt" suggests that the speaker has no respect for the attempt.
"Contemptuous" and "contemptible" are not synonymous. "Contemptible" meanings worthy of contempt, whereas "contemptuous" means a feeling contempt. A good dictionary can point out the difference between words like these.