The correct answer is: B. Two subscripts.
A two-dimensional array is an array that has two indices, or subscripts, to identify each element. The first subscript indicates the row of the element, and the second subscript indicates the column of the element. For example, in the array arr[3][4], the element at row 1, column 2 is identified by the subscript arr[1][2].
Option A is incorrect because a one-dimensional array only has one index, or subscript, to identify each element. Option C is incorrect because a three-dimensional array has three indices, or subscripts, to identify each element. Option D is incorrect because a zero-dimensional array does not have any indices, or subscripts, to identify each element.