Hey there!
I'd day your most logical answer is:
<span>d.) "Then, with that faint fleeting smile playing about his lips, he faced the firing squad; erect and motionless, proud and disdainful, Walter Mitty the Undefeated inscrutable to the last""
I hope this helps! have a good day! </span>
Answer:
I don't notice any grammatical errors.
Explanation: