The remote control of a TV emits infra-red light of wavelength 900 nm . The TV detector is made of a semiconductor whose band gap is $x$ $\mathrm{eV}$. The detector is shielded by a semiconductor optical filter whose band gap is $y $\mathrm{eV}$. From the four options below, select the best option for the TV to function.

• Correct answer
  A

  $x=1.2$ and $y=1.4$
• B

  $x=1.1$ and $y=1.8$
• C

  $x=2.2$ and $y=1.0$
• D

  $x=2.0$ and $y=1.2$

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