Final answer:
Insertion sort illustrates the concept of a sorting algorithm, which is a method to organize data in a particular order. It is commonly used as an introductory example in programming.
Step-by-step explanation:
The programming concept illustrated by the insertion sort is c) Sorting algorithm. Insertion sort is a simple sorting algorithm that builds the final sorted array (or list) one item at a time. It is much less efficient on large lists than more advanced algorithms such as quicksort, heapsort, or merge sort. However, insertion sort provides a good introduction to the concept of sorting for new programmers. This algorithm involves looping through items, often using a nested loop, where the inner loop compares the key value to the already sorted elements and inserts it into the correct position.