$\lim _{y \rightarrow 0} \frac{\sqrt{1+\sqrt{1+y^4}}-\sqrt{2}}{y^4}=$

• Correct answer
  A

  $\frac{1}{4 \sqrt{2}}$
• B

  $\frac{1}{2 \sqrt{2}(1+\sqrt{2})}$
• C

  $\frac{1}{2 \sqrt{2}}$
• D

  $\frac{1}{4 \sqrt{2}(1+\sqrt{2})}$

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