The vector $\overrightarrow{\mathrm{a}}=2\hat{\mathrm{i}}$ rotates anticlockwise in xy-plane through an angle of  ${90}^{\mathrm{o}}$. Then  change produced in the vector is ----

• A

  $\frac{1}{\sqrt{2}}(\hat{\mathrm{i}}-\widehat{\mathrm{j})}\mathrm{a}$

• B

  $\sqrt{2}(\hat{\mathrm{j}}-\widehat{\mathrm{i})}$

• C

  $2(\hat{\mathrm{j}}+\widehat{\mathrm{i})}$

• D

  $2(\hat{\mathrm{j}}-\widehat{\mathrm{i})}$