The gradient of the displacement time graph is the velocity.

Gradient of x = $\frac{y_1-y_2}{x_1-x_2}=\frac{30-40}{6-12}=\frac{-10}{-6}=\frac{5}{3}$ meters per second

Gradient of y = $\frac{y_1-y_2}{x_1-x_2}=\frac{0-40}{0-8}=\frac{-40}{-8}=5$ meters per second

Therefore the first option is false the second is also so not true, according to my calculations above the fourth option is true,and also it looks like the third is also true as the displacement is equal

Many Thanks