2. The term “Opiniojuris” signifies:
(a) Just opinion
(b) The belief that a certain practice is obligatory as a matter of law
(c) Decision of publicists on law
(d) None of these

Shouldn't the answer be C?. Opinio Juris is the legal opinion of Jurists on the matter, its definitely not a belief that a certain practice should be obligatory. The only problem with C is the word 'decision', which isn't what opinio juris is, its not a decision, but an opinion by an author on law. But given the history of printing errors and typos in the exam, the safest bet should be C.