If you add a positive constant c to the input of a function, that will have the effect of shifting the graph of the original function to the left by c units. If you subtract a positive constant c from the input of a function, that will have the effect of shifting the graph of the original function to the right by c units. The correct answer is shift it $\displaystyle\frac{\pi}{{2}}\usepackage{cmbright}\Huge\$ units to the right.