What is banquo saying in this passage?

"a heavy summons lies like lead upon me,
and yet i would not sleep: merciful powers,
restrain in me the cursed thoughts that nature
gives way to in repose! "

a.) he is having trouble sleeping.

b.) he is unyielding in his loyalty to macbeth.

c.) he feels conflict about his secret desire to be king.

d.) he is conflicted about whether he should participate in the murder.