During the civil war, rising inflation in the north meant that

a) the cost of food and other items skyrocketed.

b) many store and factory workers lost their jobs.

c) most businesses could not afford to operate.

d) the prices for most goods decreased sharply.

A. inflation means that items become more expensive. 

A) the cost of food and other items skyrocketed.

Inflation refers to an increase in the price of goods and services over a period of time. This means that purchasing power (how much a unit of money can get you) decreases. Inflation is usually caused by an excessive growth of money supply. A long sustained period of inflation is caused by money supply growing at a faster rate than economic growth.

If you're talking about after WW1 it's because basically they took the fall for starting the Great War and was given massive war debt by all the other countries from the Allies which lead them into a Great Depression.