$ATP$ synthesis in chloroplasts and mitochondria is due to a proton gradient across the membrane. Select the correct statements with respect to $ATP$ formation in chloroplasts:
$(a)$ Protons accumulate in the lumen of the thylakoid.
$(b)$ Splitting of water occurs on the inner side of the membrane.
$(c)$ Protons accumulate on the stroma side of the chloroplast.
$(d)$ $NADP$ reductase is located on the stroma side of the membrane.

• A
  Only $(a)$ and $(b)$ are correct
• B
  Only $(b)$ and $(c)$ are correct
• C
  Only $(c)$ and $(d)$ are correct
• D
  $(a), (b)$ and $(d)$ are correct