2d array Java

Which of the following statements correctly declares a two-dimensional integer array?

• int Matrix[ ] = new int[5,4];

• int Matrix[ ]; Matrix = new int[5,4];

• int Matrix[ ][ ] = new int[5][4];

• int Matrix[ ][ ] = int[5][4];

How would you get the value 6 out of the following array int[][] a = {{2, 4, 6, 8}, {1, 2, 3, 4}};? Remember each set of curly braces represents a row, or a single dimensional array.

• a [0][3]

• a [1][3]

• c) a[0][2]

• d) a[2][0]

• e) a[3][1]

How many columns does a have if it is created as follows

int[][] a = {{2, 4, 6, 8}, {1, 2, 3, 4}};?

• 3

• 4

• 2

• 1