If the (Steadily Decreasing)marginal Benefit of Another Day Spent in the Hospital

If the (steadily decreasing) marginal benefit of another day spent in the hospital is larger than the (steadily increasing) marginal cost of an additional day spent in the hospital, the

A) net benefit from the hospital stay must be positive.
B) net benefit from the hospital stay must be decreasing.
C) net benefit from the hospital stay must be increasing.
D) net benefit from the hospital stay is maximized.