The correct option is B provided that
'Provided that' are two conjunctions that are paired together to give its combined meaning 'on condition of', it also means 'if, and only if'. The speaker says that they'd go to Nepal if they have enough money, hence 'provided that' is the correct pair of conjunctions and option B is correct. 'If' cannot be paired up with 'provided', because 'if' means the same as 'provided that', hence options A and C are incorrect. 'Provided for' are paired up to give another meaning 'make available for' or 'supply to', since it is not relevant to what the sentence means, and the sentence calls for a conjunction that describes the condition that "I have enough money", option D is incorrect.