In the below graph,point $B$ indicates

$A$ stress-strain graph for a metal is shown. The part in which Hooke's law holds good is

The strain-stress plot for materials $A$, $B$, $C$ and $D$ is shown in the figure. Which material has the largest Young's modulus?

The diagram shows the change $x$ in the length of a thin uniform wire caused by the application of force $F$ at two different temperatures $T_1$ and $T_2$. The variations shown suggest that

Assertion $(A)$: Ductile metals are used to prepare thin wires.
Reason $(R)$: In the stress-strain curve of ductile metals,the length between the points representing elastic limit and breaking point is very small.

The figure shows the stress-strain curve for a given material. What are $(a)$ Young's modulus and $(b)$ approximate yield strength for this material?