What will be the change in the speed of a moving object if both speed and acceleration are positive or both are negative?

The acceleration $(a)$ - time $(t)$ graph for a body starting from rest is given below. The maximum speed of the body is (in $m/s$)

The displacement is given by $x = 2t^2 + t + 5$. The acceleration at $t = 2 \ s$ is:

The velocity $(v)-$ time $(t)$ plot of the motion of a body is shown below:
The acceleration $(a)-$ time $(t)$ graph that best suits this motion is:

Will the acceleration increase or decrease with an increase in velocity?

$A$ body starts from the origin and moves along the $x$-axis such that its position at any instant is $x = 4t^2 - 12t$,where $t$ is in seconds and $x$ is in meters. What is the acceleration of the particle in $m/s^2$?