Final answer:
In a two-dimensional array a, the output of a[2] is the third sublist. Therefore, the correct answer is option c) [3, 4, 2]. This question pertains to indexing in a programming context.
Step-by-step explanation:
The question seems to pertain to accessing elements within a two-dimensional array in a programming language, most likely Python given the syntax. When you see a = [[1,2,3],[2,4,5],[3,4,2]], this means that a is a list of lists. To access elements in a two-dimensional array, you use two indices; the first index denotes the sublist and the second index denotes the position within that sublist.
If you are asking what the output of a[2] is, then we are looking at the third sublist within a, since indexing starts at 0. Therefore, a[2] would correspond to the third sublist which is [3, 4, 2]. Hence, the correct answer to what is the output of a[2] is option c) [3, 4, 2].