What is the difference between 'affect' and 'effect'?

• A. Affect is a noun meaning to influence; Effect is a verb meaning to influence.
• B. Affect is a verb meaning to influence; Effect is a noun meaning the result.
• C. They are interchangeable.
• D. Effect is a verb meaning to influence; Affect is a noun meaning the result.

Answer: (B)

Affect and effect are about different parts of speech in everyday usage: affect is a verb meaning to influence, while effect is a noun meaning the result of a cause. Use affect when you want to say something is causing a change or influencing something else. For example, "The rain affected our plans" means the rain caused a change in what was going to happen. Use effect when you want to name the outcome or result. For example, "The rain had the effect of delaying the game" points to the result of the rain.

There is a rare verb form, to effect, meaning to bring about or cause, but that usage is not as common in typical sentences about influence. Also, affect can appear as a noun in psychology to describe a person’s emotional state, but that is a specialized usage beyond everyday writing.