The (main) thing that you would want to remember would be that, 0.4 is .4 of 1. So, when looking at your options, we would want to find something that is pretty much almost half of 1.
For example: 0.5 is half 1, so in this case, 0.4 is almost half of 1, and we would want to find an option that would be very similar.
Your correct answer would be (option b and option c).