Given a 2D array of strings, which represents a letter matrix. Your task is to rotate this matrix 90 degrees clockwise and output the result.
If the matrix is 
X 4 2 N
H 1 7 2
M 8 K I.
What is the result?
Return your answer with format <<<list of values and symbols>>>, For example, <<<A,B,C,D>>> represents a 2D array.