Representing Motion Practice Test

The position of a particle is given by the function $$x(t)$$. Which of the following mathematical expressions represents the particle's instantaneous acceleration at time $$t$$?

An object moves along the x-axis with a velocity given by $$v(t) = 3t^2 + 2t$$, where $$v$$ is in m/s and $$t$$ is in seconds. What is its displacement during the interval from $$t=1$$ s to $$t=3$$ s?