Equimolar solution implies all the aqueous solutions have the same concentration.

The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, and values above 7 indicate basicity. Among all the aqueous solutions we have in the option, NaOH has the highest value, thus it has the highest pH. 

NaOH is a strong base, meaning it completely dissociates into ions (Na+ and OH-) in water, resulting in a high concentration of hydroxide ions (OH-) and a high pH.