If $y=1+x+\frac{x^{2}}{2 !}+\frac{x^{3}}{3 !}+\ldots . \infty,$ then $\frac{d y}{d x}$ is equal to

• A

  $x$
• B

  1
• Correct answer
  C

  $y$
• D

  None of these

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