Which of the following compound shows optical isomerism? (en = ethylenediamine)?

a) cis-[Co(NH₃)₄Cl₂]

b) trans-[Co(en)₂Cl₂)

c) cis-[Co(en)₂Cl₂)

d) [Co(en)₃]

Select the correct answer u-sing the codes given below:

• A

  a and b

• B

  b and c

• C

  c and d

• D

  a, c and d