A mass $M$ performs linear simple harmonic motion. Then, the correct graph for acceleration $a$ and corresponding linear velocity $v$ is,

Acceleration $a$ versus time $t$ graph of a body in SHM is given by a curve shown below. $T$ is the time period. Then, the corresponding graph between kinetic energy KE and time $t$ is correctly represented by,

A toy car of mass $m$ is having two similar rubber ribbons attached to it as shown in the figure. The force constant of each rubber ribbon is $k$ and the surface is frictionless. The car is displaced from mean position by $x \mathrm{cm}$ and released. At the mean position, the ribbons are undeformed. The vibration period is,