Which of the following conclusions can be drawn from the result $\oint \vec{B} \cdot d\vec{A} = 0$?

Assertion: The magnetic field lines are continuous and form closed loops.
Reason: Magnetic monopole does not exist.
The correct option among the following is

$A$ 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:

The figure represents an area $A = 0.5\,m^2$ situated in a uniform magnetic field $B = 2.0\,Wb/m^2$. The area makes an angle of $60^o$ with the magnetic field. The value of the magnetic flux through the area is equal to......$Wb$.

When the surface of a sheet is parallel to the magnetic field,what is the magnetic flux linked with it?

Explain Gauss's law for magnetism.