This is just common sense.  You're trying to spend as little as possible. So,
make as few as you can of the two more expensive two products. Then, for the
rest, make as few as you can of the cheapest product.

So make 20 units of the most expensive product, A, 30 units of next most
expensive product B.  That makes 50 products, and since you must make 200
products, make the remaining 150 all C's, the least expensive.

How much will that cost?

20 units of A will cost 20(P176) =  P3520
 
30 units of B will cost 30(P88) =   P2640

150 units of C will cost 150(P44) = P6600

                      Total cost = P12760

Edwin