The baltic states have made efforts to diversify their
a. economies
c. 21 and culture
b. population
d. religion

Well they tried to diversify their ethnic diversity so the closest answer to that is C. But they've also been trying to diversify their industries.  That would fit into A.  It seems though that what most questions are looking for is the economy.  The biggest change was for industries. 

Chicken breast with a green salad in a serving of vegetables

Opposition of two melodic ideas is the  right answer