Which are prisms among the following?
A)

B)

C)

D)

Hint:
A prism is a polyhedron having a n- sided base and also ends with the same base. These two bases are connected with a number of rectangles that are parallelograms. A prism also has the same cross section along its length. So, we can check whether the given object has identical bases and the same cross section throughout its length.

Complete step by step solution:
We know that a prism is a polyhedron having two of its faces congruent and has the same cross section throughout its length. So we can check given options one by one.
Consider option A. It is a nail and it has one pointed end and another end is flat. So, it does not have identical ends. So, it is not a prism.
Consider option B. It is an unsharpened pencil. It has 2 sides hexagonal and are identical. We can also see that it has the same cross section throughout its length. So, it is a prism.
Now, consider option C. it is a pyramid. It has one end as a square and the other end is pointed. So, it does not have identical ends. So, it is not a prism
Now consider option D. it is a box. It has top and bottom congruent quadrilaterals and the sides are parallelograms. We can also see that it has the same cross section throughout its length. So, it is a prism.

So, the correct answer is option (B), un-ruled pencil and option D box.

Note:
A prism is a polyhedron having a n- sided base and also ends with the same base. These two bases are connected with a number of rectangles that are parallelograms. A prism also has the same cross section along its length. A common prism we are familiar with is a triangular prism. We must not compare it with the pyramid and make mistakes.