Which of the following will increase the sustainable rate of growth for a firm?

I.$$ Decreasing the profit margin

II$.$Increasing the dividend payout ratio

III.$$ Decreasing the capital intensity ratio

IV$.$ Increasing the target debt$-$equity ratio

$1.$ I$$and II only

$2.$ III and IV only

$3.$ II and IV only

$4.$ I, III and IV only

$5.$ I, II$,$ III and IV