Which definition best matches the verb 'underlie'?

• A. To Serve As A Basis For
• B. To Be Situated Above Something
• C. To Believe
• D. To Appear Suddenly

Answer: (A)

Underlie expresses the foundational support behind something. It means to provide the underlying basis or grounds for a result, belief, idea, or system.

The best match is to serve as a basis for, because it directly captures that sense of providing the essential foundation that explains or supports what follows. For example, economic factors underlie the policy, meaning those factors form the basis for the policy’s design and implementation.

The other options don’t fit this core sense. A literal sense of being situated above something describes a spatial relationship, which is the opposite of the common abstract usage. To believe and to appear suddenly relate to mental state or sudden action, neither of which convey the idea of providing a foundation or basis.