Marginal means...

• A. Not important
• B. Quite small
• C. On the margin or border
• D. A border or edge

Answer: (C)

The idea being tested is how the word signals location at the edge. Marginal comes from margin, the outer edge of something like a page or a boundary, so it describes something that sits at or near that edge. That makes “on the margin or border” the best fit here, because it directly conveys the position relative to the boundary. In other contexts, marginal can also mean not very important, but in this sense the emphasis is on location at the edge rather than significance. Saying “a border or edge” names the boundary itself rather than where something is, which is why the edge-focused sense is more precise.