Can you explain how to solve this problem?

Kari, inc.s book balance on Dec. 31, 2010, was $5000. In addition, Kari had the following items on its premises on Dec. 31: Check payable to Kari, Inc., dated Jan. 3, 2011, included Dec. 31 book balance $200. Postage stamp on hand not included in Dec. 31 book balance $100. Cashiers check payable to kari In., dated Dec. 28, 2010 not included in December 31 book balance $1,300 The proper amount to be shown as cash on Karis balance sheet at December 31, 2010, is

a) $6200

b) $6300

c) $6400

d) $6100