What does lady macbeth mean by “when none can call our pow’r to accompt” in these lines from act v of the tragedy of macbeth by william shakespeare?

a. she and macbeth cannot explain why they have so much power.

b. she and macbeth are calling for an increase in power.

c. she believes that she and the king are all-powerful.

d. she is expressing a fear of macduff that the king shares.