Which of the following is false about purine and pyrimidine bases?

• A. They are hydrophobic and relatively insoluble in water at the near-neutral pH of the cell
• B. At acidic or alkaline pH the bases become charged and their solubility in water increases
• C. Purines have two rings in their structure, but pyrimidine bases have only one ring
• D. At acidic or alkaline pH the bases become charged and their solubility in water decreases