The set of natural numbers forms a subset of which of the following set of numbers?

The correct option is Set of whole numbers.

Step 1: Definition of Natural Numbers
Natural numbers are the positive counting numbers starting from 1.

$\text{Natural Numbers}=\{1,2,3,4,\text{…}\}$

Step 2: Definition of Whole Numbers
Whole numbers consist of all natural numbers along with zero.

$\text{Whole Numbers}=\{0,1,2,3,4,\text{…}\}$

Step 3: Subset Relationship
A set is considered a subset of another set if every element of the first set is contained within the second set.

$\text{Set of Natural Numbers}\subset \text{Set of Whole Numbers}$

Since every natural number (1, 2, 3, 4, …) is also present in the set of whole numbers (0, 1, 2, 3, 4, …), the set of natural numbers is a subset of the set of whole numbers.

Step 4: Analysis of Other Options
- Set of irrational numbers: Irrational numbers cannot be written as simple ratios of integers (e.g., √2, π), so natural numbers do not belong to this set.
- Set of negative integers: Negative integers are numbers strictly less than zero (-1, -2, -3, …), whereas natural numbers are all positive.
- Set of non-positive integers: Non-positive integers include zero and all negative integers (0, -1, -2, -3, …), which excludes all positive natural numbers.

Therefore, the set of natural numbers forms a subset of the Set of whole numbers.