Some general principles of law are:

• good faith,

• obligation to make reparation,

• res judiciata (a matter may not, generally, be

relitigated once it has been judged on the merits),

• estoppel (the requirement of consistency in legal

argumentation), proportionality,

• lex specialis derogate legi generali (special law should prevail over general law),

• lex posterior derogate legi priori (more recent law prevails over an inconsistent earlier law),

• fair trial,

• liability for fault, and

• exhaustion of local remedies.

But IV is related to custom (objective element). The answer is B