D Has Non-Consensual Sex with V

D has non-consensual sex with V. At his trial for rape, D asserts a reasonable belief in consent. D is a man with severe learning difficulties. Which of the following represents the law:

A) D's learning difficulties are irrelevant to the question of whether his belief was reasonable.
B) D's learning difficulties mean that his belief was probably genuine and therefore he lacked MR.
C) D lacks the capacity to form MR.
D) D's learning difficulties will be taken into account in determining whether his belief was reasonable in all the circumstances.