One of the following graphs represents the titration of a triprotic acid with a strong base. Which titration curve is it?

Titration curve showing a triprotic acid's pH change with a strong base.

Titration curve depicting a rapid pH drop for a triprotic acid.

Titration curve illustrating gradual pH increase for a triprotic acid.

Titration curve showing a triprotic acid's pH leveling off with added base.