Please explain your answer as I am struggling to understand this concept.

Adams Company is a manufacturing company that has worked on several production jobs during the first quarter of the year. Below is a list of all the jobs for the quarter: Balance Job 356 $450 Job 357 1,235 Job 358 378 Job 359 689 Job 360 456 Jobs 356, 357, 358, and 359 were completed. Jobs 356 and 357 were sold at a profit of $500 on each job. What is the ending balance of Cost of Goods Sold for Adams Company at the end of the first quarter? x Oa. $456 Ob. 5. $2,685 Oc. $1,685 Od. $685