Which of the following is true regarding a fatty acid molecule in water?

A) It is positively charged at physiological pH, but can become neutral when the pH is high enough.
B) It is positively charged at physiological pH, but can become neutral when the pH is low enough.
C) It is negatively charged at physiological pH, but can become neutral when the pH is high enough.
D) It is negatively charged at physiological pH, but can become neutral when the pH is low enough.
E) It is not charged at physiological pH.