Which of the following CANNOT be weighed using a balance scale and these unit weights: 1, 4, 7, and 11?	Select:
A) 13	B) 16	C) 18	D) 19	E) 22
A. 13 (cannot be weighed)   B. 15 (can be weighed by keeping weights of 11,4 and 1 kg)   C. 17 (can be weighed by keeping weights of 11 and 7 kg)   D. 19(can be weighed by keeping weights of 11, 7 and 1kg )   E. 21 (can be weighed by keeping weights of 11, 7 and 4 kg)   13
<result>A</result>
Which of the following CANNOT be weighed using a balance scale and these unit weights: 1, 4, 7, and 11?