Based on the Information Below, How Would You Access the First

Based on the information below, how would you access the first index of the array?
Var x = [0, 1, 2, 3, 4, 5];
Var y = [x];

A) document.write(y[0]) ;
B) document.write(y[0][0]) ;
C) document.write(y[3]) ;
D) document.write(y[0][1]) ;