What is the difference between "affect" and "effect" in written English?

• A. Affect is a noun meaning the result; effect is a verb meaning to influence.
• B. Affect is a verb meaning to influence; effect is a noun meaning the result.
• C. Affect and effect are synonyms used interchangeably.
• D. Affect is a pronoun; effect is an adjective.

Answer: (B)

The difference being tested is how these two words function in a sentence. Affect is a verb meaning to influence or change something. You use it when something is having an influence on something else. For example, weather can affect travel plans. Effect, on the other hand, is a noun meaning the result or outcome of a cause. You use it when you’re talking about what happened as a result. For example, the storm had a big effect on travel.

That’s why this answer is the best: it states the standard roles clearly—affect as a verb and effect as a noun. The other options mix up parts of speech or claim they’re interchangeable, which isn’t how these words are used in ordinary writing. (There are rare, formal uses like to affect as a noun in psychology or to effect a change as a verb, but those aren’t the common everyday usage.)