If the product of the integers a, b, c and d is 770, and if 1 < a< b< c< d, what is the value of a+ d?  Choose the correct answer:
A) 10 B) 13 C) 16 D) 18 E) 21
770 = 2 * 5 * 7 * 11   So a= 2, x = 5, c= 7, d= 11   a+ d= 2 + 11= 
<gadget id="calculator">2 + 11</gadget>
<output>13</output>
13   Answer - 13
<result>B</result>
If the product of the integers a, b, c and d is 770, and if 1 < a< b< c< d, what is the value of a+ d?