At the break-even point:

A. Sales would be equal to total costs.
B. Both sales would be equal to total costs and contribution margin would be equal to total fixed costs are correct.
C. Sales would be equal to fixed costs.
D. Contribution margin would be equal to total fixed costsã

D. Contribution margin would be equal to total fixed costs

Explanation:

As we know that

break even point is the point at which the firm is earning no profit or no loss suffered

In equation, it is

Total cost = Total revenues

In addition,

The contribution margin = Sales - variable expenses

Therefore

The contribution margin = Fixed cost = break even point

If we subtract the contribution margin from the fixed cost the amount should be zero which implies the break even point

The answer is below

Explanation:

1) Opportunity cost of producing rice:

For country A, opportunity cost of producing rice = 100 pounds of broccoli / 200 pounds of rice = 1/2 pounds of broccoli

For country B, opportunity cost of producing rice = 120 pounds of broccoli / 160 pounds of rice = 3/4 pounds of broccoli

Opportunity cost of producing broccoli:

For country A, opportunity cost of producing broccoli = 200 pounds of rice / 100 pounds of broccoli = 2 pounds of rice

For country B, opportunity cost of producing broccoli = 160 pounds of rice / 120 pounds of broccoli = 4/3 pounds of rice

2) The country with comparative advantage is the country with lower opportunity cost.

Country A has a comparative in producing rice (1/2 pounds of broccoli < 3/4 pounds of broccoli)

Country B has a comparative in producing broccoli (4/3 pounds of rice <  2 pounds of rice)

3) For better off trade, the price should lie between two different opportunity costs.

Therefore, the price per pound of broccoli in terms of pounds of rice should lie between 4/3 and 2 pounds of rice