The correct answers are the following.
The opportunity cost of producing 70 more bagels is 100.
The opportunity cost of producing fifty more croissants is 70.
The opportunity cost is the factor or element that you are losing when you make a decision when you choose something else. IN business, when you decide over "A," there is something that you lose by having not decided for "B." That is the opportunity cost. So every time you are about to make a business decision or operations decision, remember there is a trade-off included.