Answer:
A. This is a sentence fragment because it is a dependent clause. A correct version could be: Whereas his mother, Diana, held the title of Princess of Wales, his father held the title Prince of Wales.
Step-by-step explanation:
The preceding sentence is a fragment sentence since it does not represent a full thought. Because of the term "whereas" it became a dependent clause. To fix it, remove the term "whereas." whereas is not capitalized because it is not a proper noun or adjective.