What is the effect of a ten-fold increase in pressure on $k_p$ in the reaction $N_2(g)\: 3H_2(g) \: \leftrightharpoons \: 2\: NH_3 (g)$ at equilibrium ?

Question

$\begin {array} {1 1} (1)\;A\: ten-fold\: increase & \quad (2)\;A\: ten-fold\: decrease \\ (3)\;No\: change & \quad (4)\;Equal\: to\: K_C \end {array}$