Which of the following is the most primitive ancestor of humans?

The number of possible enantiomeric pairs that can be produced during mono-chlorination of $2$-methylbutane is

$A$ wind with speed $40\,m/s$ blows parallel to the roof of a house. The area of the roof is $250\,m^2.$ Assuming that the pressure inside the house is atmospheric pressure,the force exerted by the wind on the roof and the direction of the force will be $(\rho_{air} = 1.2\,kg/m^3)$

$A$ motor-car tyre has a pressure of $2\, atm$ at $27\,^{\circ}C$. It suddenly bursts. If $\gamma = \frac{C_p}{C_v} = 1.4$ for air,find the resulting temperature. (Given $4^{1/7} = 1.219$)

$A$ mass $M$ hangs on a massless rod of length $l$ which rotates at a constant angular frequency $\omega$. The mass $M$ moves with steady speed in a circular path of constant radius $r$. The angular momentum of $M$ about point $A$ is $L_A$,which lies in the positive $z$-direction,and the angular momentum of $M$ about point $B$ is $L_B$. Which of the following statements is correct for this system?