Using standard alphabetical filing rules, which name is filed last: Nina Pascual, Nina Pascua, Nina Pasco, Nina Pascal?

The correct answer is A. Nina Pascual

Indexed surname first, the filing order is PASCAL, Nina → PASCO, Nina → PASCUA, Nina → PASCUAL, Nina. The name filed last is Nina Pascual. All begin with "Pasc". Comparing the next letters, a (Pascal, Pascua, Pascual) comes before o (Pasco), so Pasco is filed last; "Pascua" comes before "Pascual" because nothing comes before something.