What are the shapes of ethyne and methane?

Two spheres $A$ and $B$ are kept very near to each other. $A$ is negatively charged and $B$ is earthed. The true statements are:
$(A)$ Charge on $B$ is zero
$(B)$ Potential at $B$ is zero
$(C)$ Charge is uniformly distributed on $A$
$(D)$ Charge is non-uniformly distributed on $A$

Match the following:

Column-$I$	Column-$II$
$(1)$ Oxytocin	$(p)$ Stimulates the secretion of thyroid hormone
$(2)$ Vasopressin	$(q)$ Act on the smooth muscles
$(3)$ $FSH$ and androgens	$(r)$ Stimulates resorption of water
$(4)$ $TSH$	$(s)$ Regulate spermatogenesis

$A$ uniform but time-varying magnetic field $B(t)$ exists in a circular region of radius $a$ and is directed into the plane of the paper,as shown. The magnitude of the induced electric field at point $P$ at a distance $r > a$ from the centre of the circular region is:

The probability that a student is not a swimmer is $1/5$. What is the probability that $4$ out of $5$ students are swimmers?

The equation $16 x^2+y^2+8 x y-74 x-78 y+212=0$ represents: