11. Add commas to the following sentences, and for each sentence briefly justify why the commas were needed.

a. Although Apple's sales remained stagnant in Q2 its stock price rose.

b. Jones Company which is based in India is privately held.

c. We need to audit the company's accounts receivable accounts payable and cash accounts.

d. Presto will make an upfront payment and Stadium Co. will use the funds toward capital improvements