Step 1: Recall the function of a gusset plate.
A gusset plate is a steel plate used to connect two or more structural steel members at a joint.
Step 2: Identify the correct option.
It is commonly used in trusses, bridges, and framed structures to transfer forces between connected members.
Hence,
\[
\boxed{\text{Gusset plate}}
\]
is the correct answer.
Therefore,
\[
\boxed{(D)}
\]
is the correct answer.