What does the term "marginal" mean in economics?

According to the classical model, a 10-percent increase in the money supply, holding everything else constant, will lead to

a. a 10% increase in prices, a 10% increase in the real wage, and a 10% increase in interest rates. b. a 10% increase in prices, a 10% increase in the money wage, and a 10% increase in interest rates. c. a 10% increase in prices, a 10% increase in the money wage, and no change in interest rates. d. a 10% increase in prices and no change in the money wage or interest rates. e. none of the above.

What is his expected loss after installing the safety equipment

a. $20,000 b. $50,000 c. $100,000 d. $125,000