Which two statements are true for a two-dimensional array?

Which two statements are true for a two-dimensional array?

A.
It is implemented as an array of the specified element type.

B.
Using a row by column convention, each row of a two-dimensional array must be of the same
size

C.
At declaration time, the number of elements of the array in each dimension must be specified

D.
All methods of the class Object may be invoked on the two-dimensional array.