If $5 f(x)+3 f\left(\frac{1}{x}\right)=x+2$ and $y=x f(x)$, then $\frac{d y}{d x}$ at $x=1$ is equal to

• A

  $14$
• Correct answer
  B

  $\frac{7}{8}$
• C

  $1$
• D

  $7$

Hence, the correct answer is option: 'B'.