The prefix meaning "within" is

• A. In-
• B. Inter-
• C. Intra-
• D. Infra-

Answer: (C)

Within implies being inside the boundaries of something. The prefix that expresses this exact sense is intra-. It shows up in words like intramural (within the walls or confines of an organization), intrapersonal (within a person), or intranet (a network inside an organization). The other prefixes don’t convey that inner, inside relationship: inter- means between or among, infra- means below or beneath, and in- is a more general form meaning into/onto or, in some cases, negation, but not specifically “within.” So intra- is the precise way to say inside or within.