In which condition can migration create a dual effect on an area's economy?

Correct answer: Out-migration causes labour loss but remittances also arrive

The direct answer is A. Migration can produce both a cost and a benefit for the source area. When workers leave, the area may lose labour, skills, and part of its local productive capacity. At the same time, migrants may send money home; these remittances can raise household income and help pay for food, education, health care, housing, or small investments. A is correct because it clearly presents these opposite effects together. B is wrong because if nobody leaves, there is no out-migration effect to analyse. C is wrong because a change in birth rate is a demographic process, not a dual migration effect. D is wrong because a zero death rate is not a description of migration and does not identify two economic consequences. The effects are not automatically equal or positive in every place; the important idea is that labour loss and money received can occur at the same time. Memory cue: migration may take workers away but send income back.