Getting this question right depends on checking two separate facts about the Disciplinary Committee rather than just one, its total strength, and the source of each of its members.
Only the option that gets both the total strength of three and the two-elected-plus-one-outside-co-opted composition correct matches Section 9(1).
The correct answer is three members, two elected from the Council's membership and one co-opted advocate possessing the prescribed qualifications, who is not a member of the Council.
A quick way to approach this question is to sort the four options into two groups by their stated total strength, and only then look at how the members are chosen within the correct group.
Filtering first by total strength, three, not five, and then by whether an outside co-opted member is included leaves only one option consistent with Section 9(1).
So the correct answer is three members, two elected from the Council's membership and one co-opted advocate possessing the prescribed qualifications, who is not a member of the Council.