A 25.0-mL sample of asolution of an unknown compound is titrated with a 0.115 M NaOHsolution. The titration curve above was obtained. Theunknown compound is .

NOTE: the curve has "mL of 0.115M NaOHadded to flask" (ranging from 0-45 mL in increments of 5 mL) alongx-axis, and "pH of solution in flask" (ranging from 2-12.0 inincrements of 2) along the y-axis. It shows one equivalencepoint at 25mL along the x-axis and between a pH of 7 and 8 alongthe y-axis. The curve looks like it is for a monoproticsubstance, and is in the shape of a very lazy "S" or snake.

a. a strong acid

b. a strong base

c. a weak acid

d. a weak base

e. neither an acid nor abase