Which of these is true?

Multiple select question.

The algorithm for matrix multiplication uses $\backslash$Theta $(3$n$)$ operations.

The algorithm for matrix multiplication uses $\backslash$Theta $($n$3)$ operations.

There are matrix multiplication algorithms that are faster than $\backslash$Theta $($n$3).$

The algorithm for matrix multiplication uses $\backslash$Theta $($n$2)$ operations.