Which of the following is the set of integers?

The set of integers encompasses all whole numbers both positive and negative, including zero. This is represented by the notation Z, which includes the elements {..., -3, -2, -1, 0, 1, 2, 3, ...}. Each integer is a complete unit without fractions or decimals, making this selection accurate as it captures the entirety of integers.

In contrast, the other sets provided do not meet this definition. The first set consists only of positive whole numbers starting from 1, excluding zero and negative integers. The second set includes zero and positive whole numbers but still omits any negative integers. Lastly, the fourth set consists of rational numbers expressed as fractions, which does not include whole numbers, thus failing to align with the definition of integers. This distinction highlights why the correct answer effectively represents the full scope of integers.