Q51,p3,d14. Consider an imaginary disk with 40 cylinders. A request come to read a block on cylinder 11. While the seek to cylinder 11 is in progress, new requests come in for cylinders 1, 36,16, 34, 9 and 12 in that order. The number of arm motions using shortest seek first algorithm is

(A) 111 (B) 112

(C) 60 (D) 61 

Answer D

Explanation. 

11->12->9->16->1->34->36.=1+3+7+15+33+2=61.