Which of the following examples represents periodic motion?

The figure depicts four $({x\text-t})$ plots for the linear motion of a particle.

(a)
(b)
(c)
(d)

Which of the following is true​​​​?

A particle is in linear simple harmonic motion between two points, $A$ and $B$, $10~\text{cm}$ apart. (Take the direction from $A$ to $B$ as the positive direction.) The signs of velocity, acceleration, and force on the particle when it is at $3~\text{cm}$ away from $A$ going towards $B$ are:

Which of the following relationships between the acceleration $a$ and the displacement $x$ of a particle involves simple harmonic motion?
1. $a =   0 . 7 x$
2. $a =   - 200 x^{2}$
3. $a =   - 10 x$
4. $a =   100   x^{3}$

A spring balance has a scale that reads from 0 to 50 kg. The length of the scale is 20 cm. A body suspended from this balance, when displaced and released, oscillates with a period of 0.6 s. What is the weight of the body?

1. 219 N

2. 196 N

3. 223 N

4. 225 N

A spring having a spring constant of $1200$ N/m is mounted on a horizontal table as shown in the figure. A mass of $3$ kg is attached to the free end of the spring. The mass is then pulled sideways to a distance of $2.0$ cm and released. The frequency of oscillations will be:
    

A spring having a spring constant of $1200$ N/m is mounted on a horizontal table as shown in the figure. A mass of $3$ kg is attached to the free end of the spring. The mass is then pulled sideways to a distance of $2.0$ cm and released. The maximum acceleration of the mass is: