Consider an array a = 1 2 3 4 5 and condition i + 2 =j. Lets take i =0 and j =2 for this example.
Work 1,
x = a[0+2] = 3
a[2] = 3 + 1 = 4; which means a = 1 2 4 4 5
return a[0+2] - 3 = 4 -3 = 1
Work 2
t1 = 0 + 2 = 2
t2 = a[2] = 3
a[2] = 3 + 1 = 4, which means a = 1 2 4 4 5 again
return t2 - 3 = 3 -3 =0
Hence S1 is false when i + 2 =j. S2 will also be false, since we cant explicitly say the performance of work2 will always be better than work1.
Hence answer is A