The option that could be included in a list of negative impacts of emigration on the country of origin is "brain drain." Brain drain refers to the emigration of highly skilled or educated individuals, which can lead to a loss of talent and diminish the country's human capital.
The other options you provided—"increased GDP" and "remittances"—are generally considered positive impacts, while "population increase" is not typically associated with emigration, as emigration usually leads to a decrease in population.