Which of the following sentences is most conventional in spelling, punctuation, and mechanics?

a. In retracing his path, the courier was worryed that he might have omitted something.

b. In retracing his path, the courier was worried that he might have omitted something.

c. In retraceing his path, the courier was worryed that he might have omited something.

d. In retraceing his path, the courier was worried that he might have omited something.