What is the opposite of fickle?

What is the opposite of fickle?
A: Courageous
B: Sincere
C: Steadfast
D: None of these

Sincere is the opposite of fickle which means inconsistent. This question tests vocabulary skills in English exams. Sincerity implies reliability contrasting with fickleness. However steadfast (constant) is a stronger antonym suggesting a possible error in options. Assuming intent answer is B.