What is Malcolm's primary reason for considering himself unfit to rule Scotland in Act 4 of "Macbeth"?
a) He believes he lacks the necessary military prowess to defend the kingdom.
b) He fears he will succumb to the same temptations and vices as Macbeth, becoming a tyrant.
c) He thinks he lacks the support of the Scottish nobles and would face rebellion if crowned.
d) He feels unprepared for the responsibilities of kingship and prefers a life of freedom