A manufacturing company is working to decrease its cash conversion cycle. The firm has increased inventory levels to support its sales growth. They have increased their inventory turnover from $2\mathrm{.}5$ times to $3\mathrm{.}3$ times per year. The company has a days$$ payable of $20$ and a days$$ receivable of $45$ with normal credit terms of Net $30.$ The company wishes to decrease its cash conversion cycle and can which of the following to do so$?$

I$)$ Increase the DPOs by paying vendors later

II$)$ Decrease the DPOs by paying vendors sooner

III$)$ Enforce tougher restrictions on current customers to collect closer to the Net $30$ terms

IV$)$ Adopt a less restrictive credit policy with their customers

I and III

II and IV

IV only

I, II$,$ and III