The most alkaline solution would have a pH of d) 14.
pH is a scale that measures how acidic or basic a solution is, with 7 being neutral. Values lower than 7 indicate acidity, while values higher than 7 indicate alkalinity. A solution with a pH of 14 is considered highly alkaline, commonly associated with strong bases like sodium hydroxide. Therefore, among the options provided, the highest pH value, which indicates the most alkaline solution, is 14.