In zero-based indexing, what index refers to the first element of an array?

• A. 0
• B. 1
• C. -1
• D. 2

Answer: (A)

In zero-based indexing, counting starts at zero, so the first element sits at position zero. The second element is at one, the third at two, and so on. Therefore, the index for the first element is zero. The other numbers would refer to later elements (one is the second, two is the third), and while some languages use negative indexing to access elements from the end, that does not point to the first element. So zero is the correct index for the first element.