The answer is
d. kidney stones
She is more likely tp have it for about 50%
A buffer is a solution encompassing a weak acid and its conjugate base in alike amounts. This combination reduces the pH change upon addition of strong acid or base by converting H1+ (or OH1-) to weaker acids or bases. This primarily consist of compounds that stabilize the pH of a solution by removing or replacing hydrogen ions. Also, substances that resist change in pH.
The reason is two fold, the first is the active volcano of Kilauea implies there is a lot of heat under the big island of Hawaii, and that heat causes the island to be buoyed up. However, the other islands do not have active volcanos, are colder, and have subsided, the 2nd is, because the volcanoes on the older islands are dormant, those islands are and are no longer growing and are steadily eroding away.