The following question has a sentence with three parts marked as (a), (b), (c). Read each sentence part to determine whether there is any error in any part and indicate your response against the corresponding letter, i.e., (a) or (b) or (c). If you find no error, your response should be indicated as (d).
a: Even in the grimmest times in prison, when my comrades and I were pushed to our limits,
b: I would see a glimmer of humanity in one of the guards, perhaps just for a second,
c: but it was enough to reassure me and keep me going.