The resulting variable x$=[$zeros$(3,1),$ones$(3,1),2*$zeros$(3,1)]^3$ is a

A$.$ matrix variable

B$.$ column vector variable

C$.$ indicates a comment, everything to the right is ignored

D$.$ row vector variable

E$.$ suppresses output of the command

F$.$ string variable

G$.$ Cannot tell from the information given.

H$.$ scalar variable