Step 1: Check segment 1, "Your account should."
This sets up a modal verb "should" correctly before the main verb, which is a normal and grammatically sound structure.
Step 2: Check segment 2, "have been credited."
This is the passive perfect form, "should have been credited," which correctly shows an action that was supposed to happen to the account. The tense and voice both fit.
Step 3: Check segment 3, "with three months' interest."
"Three months'" is a correct plural possessive, showing interest that belongs to a period of three months. This phrase is grammatically sound.
Step 4: Put the full sentence together.
"Your account should have been credited with three months' interest" reads as a complete, correctly formed sentence with no faulty segment.
Final Answer:
Since no segment carries an error, option D (no error) is correct. \[ \boxed{\text{Option D}} \]