we are given,

1/0.001 < (1/10)^(n-4) , this can be written as

10^3 < (10^-1)^(n-4) , upon further simplification

10^3 < (10) ^(4-n) , applying inequality to the exponents , we get

3< 4 - n , subtracting both side by 4

-1< -n , multiplying both sides by -1 and flipping the inequality, we get

1> n

take different values of n ,

case 1)
n = 0.99

A = I n-1I = I 0.99 - 1 I = I - 0.01I = 0.01
B = 1-n = 1 - 0.99 = 0.01

thus A = B for case 1

case 2 )
n= 0

A = I n - 1 I = I -1 I = 1
B= 1-n = 1

for this case also A=B

now take an extreme case like n = -1000

case 3 ) n = -1000

A= I n-1 I = I -1000 - 1 I = I -1001 I = 1001
B = 1- n = 1 - (-1000) = 1 + 1000 = 1001

thus for this case too A = B

hence we can conclude that A = B ( option c)