According to the text regarding the chemiosmotic hypothesis in photosynthesis:

• Statement (a) is Correct: The splitting of water molecules takes place on the inner side of the membrane (associated with PS II), releasing protons into the lumen (Source 110).
• Statement (b) is Correct: As a result of water splitting and electron transport, protons accumulate within the lumen of the thylakoids, creating a proton gradient (Source 110).
• Statement (d) is Correct: The NADP reductase enzyme is located on the stroma side of the membrane, where it uses protons from the stroma to reduce NADP+ to NADPH + H+ (Source 95, 111).
• The breakdown of the proton gradient leads to ATP synthesis (Source 110).