Identify the correct output signal \( Y \) in the given combination of gates for the given inputs \( A \) and \( B \) shown in the figure.
A particle is moving in a straight line. The variation of position $ x $ as a function of time $ t $ is given as:
$ x = t^3 - 6t^2 + 20t + 15 $.
The velocity of the body when its acceleration becomes zero is: