Everything has to be less than 4 which leaves us with C and F, but Fs dot is shaded in which means it is less than or equal to but it is only less than so it is F.
If you look x is less than 4 meaning that all values are lower than 4. We also know that 4 is not included due to the fact that the less than symbol doesn't have a line under it. F is the only line that meets all of the criteria.
