Which of the following do not exist?

Which of the following statements regarding magnetic lines of force is correct?

Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ Magnetic monopoles do not exist.
Reason $(R) :$ Magnetic field lines are continuous and form closed loops.
In the light of the above statements, choose the most appropriate answer from the options given below.

$VS$ is the unit of which physical quantity?

$A$ uniform magnetic field of strength $B=2 \text{ mT}$ exists vertically downwards. These magnetic field lines pass through a closed surface as shown in the figure. The closed surface consists of a hemisphere $S_1$,a right circular cone $S_2$,and a circular surface $S_3$. The magnetic flux through $S_1$ and $S_2$ are respectively:

What is the difference between Gauss's law in electrostatics and Gauss's law in magnetism?