An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and the eye piece is 36 cm and the final image is formed at infinity. The focal length f_o of the objective and the focal length f_e of the eye piece are

• A

  ${\mathrm{f}}_{\mathrm{o}}=45\mathrm{cm}\text{ and }{\mathrm{f}}_{\mathrm{e}}=-9\mathrm{cm}$

• B

  ${\mathrm{f}}_{\mathrm{o}}=7.2\mathrm{cm}\text{ and }{\mathrm{f}}_{\mathrm{e}}=5\mathrm{cm}$

• C

  ${\mathrm{f}}_{\mathrm{o}}=50\mathrm{cm}\text{ and }{\mathrm{f}}_{\mathrm{e}}=10\mathrm{cm}$

• D

  ${\mathrm{f}}_{\mathrm{o}}=30\mathrm{cm}\text{ and }{\mathrm{f}}_{\mathrm{e}}=6\mathrm{cm}$