The correct answer is A, inflation. When the Federal Reserve raises interest rates, it is implementing a tight (contractionary) monetary policy designed to slow down economic activity. Higher interest rates make borrowing more expensive for consumers and businesses, which reduces spending and investment. This decrease in demand helps cool down rising prices, which is the primary objective when inflation is too high.

Inflation occurs when there is too much money chasing too few goods, leading to rising prices. By increasing rates, the Fed reduces the money supply and credit availability, thereby stabilizing price levels.

Choice B, recession, is incorrect because raising interest rates can actually contribute to slowing the economy further, not stimulate it. To combat a recession, the Fed would typically lower interest rates to encourage borrowing and spending.

Choice C, unemployment, is also incorrect because higher interest rates can sometimes increase unemployment by slowing business activity. Choice D, deficit spending is related to fiscal policy controlled by Congress, not the Federal Reserve.

Thus, interest rate hikes are primarily used to combat inflation, making choice A the correct answer.