In C programming, which statement best describes how the bubble sort algorithm works when sorting an array in ascending order?

Introduction / Context:
Bubble sort is one of the simplest sorting algorithms taught in introductory C programming courses. The original question asked to write a C program for bubble sort. For multiple choice testing, it is common to ask about the core idea behind the algorithm rather than the exact code. This question checks whether you know that bubble sort repeatedly compares adjacent elements and swaps them when they are out of order, performing several passes until the list is sorted.

Given Data / Assumptions:

• We are sorting a one dimensional array of elements in ascending order.
• The algorithm should use the bubble sort method, not merge sort, quick sort, or heap sort.
• Adjacent elements are compared pairwise.
• Multiple passes over the array are allowed until no swaps are required.

Concept / Approach:
In bubble sort, the array is traversed repeatedly. During each pass, the algorithm compares each pair of adjacent elements. If the element on the left is greater than the element on the right, they are swapped. After the first pass, the largest element bubbles up to the end of the array. On the next pass, the same process repeats for the remaining unsorted part of the array. The algorithm stops when a complete pass occurs with no swaps, which means the array is sorted. This behavior is quite different from divide and conquer approaches or heap based algorithms.

Step-by-Step Solution:
Step 1: Recall that bubble sort works with adjacent comparisons and swaps, not with splitting or merging arrays. Step 2: Think about how the largest value moves to the end after each full pass over the array. Step 3: Recognize that the algorithm must repeat passes until there are no more swaps, indicating that all elements are in order. Step 4: Choose the option that explicitly mentions repeated adjacent comparisons, swaps when out of order, and multiple passes.

Verification / Alternative check:
You can verify by comparing bubble sort with other named algorithms. Merge sort divides and merges arrays, heap sort uses a heap data structure, and selection based approaches choose a minimum or maximum element each time. None of these rely solely on repeated adjacent swapping. Only bubble sort uses the simple pattern of comparing neighbors and bubbling values to one side of the array, which matches option A.

Why Other Options Are Wrong:
Option B describes merge sort, not bubble sort. Option C roughly matches selection sort logic, which selects the smallest element and places it in the correct position. Option D describes heap sort, which uses a heap structure. Option E introduces a hash table approach that is not a common sorting algorithm and does not match the defined behavior of bubble sort.

Common Pitfalls:
A common pitfall is to confuse bubble sort, selection sort, and insertion sort because they are all simple comparison based sorts. Another mistake is to assume that any algorithm making multiple passes over an array is bubble sort. Remember that bubble sort specifically relies on repeated adjacent comparisons and swaps that move extremes to the ends. In real world code, bubble sort is rarely used for large datasets due to its time complexity, but it remains a useful teaching tool.

Final Answer:
It repeatedly compares each pair of adjacent elements and swaps them if they are in the wrong order, making multiple passes until no more swaps are needed