Net primary and secondary income balance

Steps:

• Net primary income = exports received ($100bn) - imports paid ($120bn) = -$20bn
• Net secondary income = transfers received ($20bn) - transfers paid ($15bn) = +$5bn
• Current account balance = net primary + net secondary = -$20bn +$5bn = -$15bn

Why B is correct:

• Balance of payments definition: current account includes net primary (investment) income plus net secondary (transfer) income flows.

Why the others are wrong:

• A. -$10bn: Misadds nets as -$20bn + $10bn (wrong secondary figure).
• C. -$30bn: Reverses secondary net to -$10bn and subtracts from primary.

Final answer: B