Explanation:
A natural number is any positive integer from 1 onwards. The cube of a natural number is obtained by multiplying the number by itself twice. For example, the cube of 2 is 2 × 2 × 2 = 8.

In order to determine whether the set of cubes of natural numbers is finite or infinite, we need to consider the following:

1. Definition of a set: A set is a collection of distinct objects, which can be numbers, letters, or any other type of entity.

2. Definition of a finite set: A set is said to be finite if it contains a specific number of elements, and we can count them. For example, the set {1, 2, 3} is finite because it contains three elements.

3. Definition of an infinite set: A set is said to be infinite if it contains an unlimited number of elements, and we cannot count them. For example, the set of natural numbers {1, 2, 3, ...} is infinite because it goes on forever.

4. Calculation of cubes of natural numbers: If we calculate the cubes of natural numbers, we get the following sequence of numbers: 1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, ... and so on.

From the above sequence, we can see that the set of cubes of natural numbers is an infinite set because it goes on forever and we cannot count all the elements. Therefore, the correct answer is option 'B' (an infinite set).