Step 1: The question asks for the FALSE statement about Graves disease, so review each option for accuracy.
Step 2: Graves disease is an autoimmune disorder (b) driven by stimulating thyrotropin receptor antibodies (TRAb), which causes overproduction of thyroid hormone and so produces hyperthyroidism (a). It presents as a diffuse toxic goitre (d). All three of these are true.
Step 3: Like most autoimmune thyroid disease, Graves is far more common in women - roughly 8 to 10 times more common in women than men, typically affecting younger women under 40. Therefore the claim that it is common in males is false.
Step 4: Distractor check - (a), (b) and (d) are all correct features, so they cannot be the answer. The false statement is (c), common in male.