If a vector $2\hat{\mathbf{i}}+3\hat{\mathbf{j}}+8\hat{\mathbf{k}}$ is perpendicular to the vector $4\hat{\mathbf{j}}-4\hat{\mathbf{i}}+\alpha \hat{\mathbf{k}}$, then the value of $\alpha$. is

• A

  $1/2$

• B

  $-1$

• C

  $-1/2$

• D

  1