Let's find the decimal value of each letter choice.
Choice A: This choice is already in decimal value.
Choice B: To turn this into a decimal, divide this by 100%. You get 0.4. This matches with choice A.
Choice C: To turn this into a decimal, divide this by 100%. You get 0.04. This does not match with A and B.
Choice D: 2/5 can be turned into 40/100. 40/100 can be converted into the decimal of 0.4. This matches with choices A and B.
Thus, the only different answer choice is C. That's your answer. I hope this helps! :)
