Aluminum hydroxide懸液劑之處方如下，則選項中所列，何者作為防腐劑使用？ Aluminum hydroxide compressed gel 326.8 g Sorbitol solution 282 mL Syrup 93 mL Glycerin 25 mL Methylparaben 0.9 g Propylparaben 0.3 g Flavor qs Purified water, to make 1,000 mL