Which of the following gives the best estimate for the pH of a 5x10-4 M Sr(OH)2(aq) solution at 25°C ?

a. about pH 7.7, because Strontium Hydroxide is a weak base and is monohydroxyl
b. about pH 10.3. because Strontium Hydroxide is a strong base and is monohydroxyl
c. about pH 11, because Strontium Hydroxide is a strong base and is polyhydroxyl
d. about pH 8.4, because Strontium Hydroxide is a weak base and is polyhydroxyl