The "ElementAt" function is a LINQ extension method available on arrays, lists, and all other IEnumerable types. This question can be solved purely based on logic given the following information: 1. The implementation of ElementAt uses an IEnumerable object. It does not cast it to anything else inside the implementation. 2. ElementAt takes a single integer parameter that indicates the index of the element to retrieve in the collection. If it is 0 then the first element is returned, if it is 1 then the second element is returned, and so on. 3. For an array "arr", arr.ElementAt(x) produces the same value as arr[x], but this question addresses whether or not it produces that result in the same way. The question is, what is the time complexity (WORST case) of the ElementAt function for an array of size n?

O(1)

O(log n)

O(n)

O(n log n)

O(n * n)