A transformer with efficiency $80\%$ works at $4\mathrm{ }\mathrm{kW}$ and $100\mathrm{ }\mathrm{V}$. If the secondary voltage is $200\mathrm{ }\mathrm{V},$ then the primary and secondary currents are respectively

• Correct answer
  A

  $40\mathrm{ }\mathrm{A}$ and $16\mathrm{ }\mathrm{A}$
• B

  $16\mathrm{ }\mathrm{A}$ and $40\mathrm{ }\mathrm{A}$
• C

  $20\mathrm{ }\mathrm{A}$ and $90\mathrm{ }\mathrm{A}$
• D

  $40\mathrm{ }\mathrm{A}$ and $20\mathrm{ }\mathrm{A}$

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