A scientist used a unique two-color code to identify each of the test subjects involved in a certain study. If the scientist found that choosing from among five colors produced enough color codes to identify all but 5 of the test subjects, how many test subjects were in the study? (Assume that the order of the colors in the codes does not matter.)	Select the correct option.
A) 7	B) 10	C) 15	D) 17	E) 20
5152 = 10   The number of test subjects is  10 + 5= 
<gadget id="calculator"> 10 + 5</gadget>
<output>15</output>
15   The answer is 15.
<result>C</result>
A scientist used a unique two-color code to identify each of the test subjects involved in a certain study. If the scientist found that choosing from among five colors produced enough color codes to identify all but 5 of the test subjects, how many test subjects were in the study? (Assume that the order of the colors in the codes does not matter.)