f(x) or y = |X| which means that for any value of x, the value of y will be positive since x is in an absolute value. the line is going to be passing through the origin since it follows this following expression (y=ax). if you add +3 like given in choice (D): f(x)=|x|+3, the function now follows the expression (y=ax+b) which means that the value of y will increase based on the value of (b), we have (b) here to +3 so the value of (y) will increase 3 points upward making (D) the right answer.
