I guess answer is C.
suppose mov a,[1000] // here mov instruction will move the data irrespective of integer/string value. So option A & B are correct.
suppose mov b,#5 // Here we are stroing the value 5 into a i.e a=5 but we cant do vice versa ie mov #5,b . Here we are checking the condition. So option d is also correct.
Option c, as their is no such condition that Integers can be moved conditionally.