The adjacent graph shows the extension ($\Delta l$) of a wire of length $1 \mathrm{m}$ suspended from the top of a roof at one end and with a load w connected to the other end. If the cross-sectional area of the wire is ${10}^{-6}{ \mathrm{m}}^2$, calculate from the graph the Young's modulus of the material of the wire.

• A

  $1.0\times {10}^{11} \mathrm{N}/{\mathrm{m}}^2$

• B

  $2.0\times {10}^{11} \mathrm{N}/{\mathrm{m}}^2$

• C

  $4.0\times {10}^{11} \mathrm{N}/{\mathrm{m}}^2$

• D

  $6.0\times {10}^{11} \mathrm{N}/{\mathrm{m}}^2$