A power transmission line feeds input power at $2300 \mathrm{V}$ to a step down transformer with its primary windings having $4000$ turns. The output power is delivered at $230 \mathrm{V}$ by the transformer. If the current in the primary of the transformer is $5 \mathrm{A}$ and its efficiency is $90 \%$, the output current would be:

• A

  $35 \mathrm{A}$
• B

  $25 \mathrm{A}$
• C

  $50 \mathrm{A}$
• Correct answer
  D

  $45 \mathrm{A}$

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