Pick up the correct statement from the following:

• For thin structures subjected to wetting and drying, the water cement ratio should be 0.45
• For mass concrete structures subjected to wetting and drying, the water ratio should be 0.55
• For thin structures which remain continuously under water, the water-cement ratio by weight should be 0.55
• For massive concrete structures which remain continuously under water, the water cement ratio by weight should be 0.65
• All the above.