Many people are allergic ______ nuts.

• A. With
• B. To
• C. From
• D. About

Answer: (B)

The key idea here is the standard way English expresses what triggers an allergy. When we say someone is allergic to something, the preposition to introduces the substance that causes the reaction. So, many people are allergic to nuts is the natural, correct phrasing.

Using other prepositions doesn’t fit how this condition is described. With nuts would imply a relation in some other sense, from nuts or about nuts sounds unidiomatic and would change the meaning. Allergic from nuts isn’t how English describes the source of an allergy either, and allergic about nuts isn’t used to express a medical reaction.