I think it makes it more easier if you simplify the inequality.
4x + 20 < 40 First subtract 20 on both sides
4x + 20 - 20 < 40 - 20
4x < 20 DIvide 4 on both sides to get the variable "x" by itself
x < 5 [x is less than 5, so x represents the numbers that are less than 5]
[Note:
If the sign is < or >, you use an open circle.
If the sign is ≤ or ≥, you use a closed circle.]
Your answer is the 1st option because the solution is any number that is less than 5