In zero-based indexing, how do you access the first element of an array named arr?

• A. arr[0]
• B. arr[1]
• C. arr[-1]
• D. arr.first

Answer: (A)

In zero-based indexing, the first item is at index 0. Accessing elements uses the array name with brackets around the index, so the first element of arr is arr[0]. If you used 1, you’d get the second element, since indexing starts counting from 0. A negative index isn’t used to get the first element in this scheme (in some languages like Python, -1 refers to the last element). The form with a dot, like arr.first, isn’t the bracket-based indexing described here.