In light reaction of photosynthesis, plastocyanin facilitates the transfer of electrons from:

• A

  PS-I to ATP synthase

• B

  PS-II to $\mathrm{Cyt}.{\mathrm{b}}_6/\mathrm{f}$ complex

• C

  Cyt ${\mathrm{b}}_6/\mathrm{f}$ to PS- I

• D

  PS-I to ${\mathrm{NADP}}^{+}$