The correct answer is ulnar styloid process, styloid process of ulna, ulna. The question is asking for the number 1 item in a list, and the options given are different parts of the ulna bone. The ulnar styloid process and styloid process of ulna are both specific structures within the ulna bone, while "ulna" refers to the entire bone itself. Therefore, all three options are correct answers for the number 1 item.