Incorrect: The car who picked her up was silver.
Correct: The car that picked her up was silver.
Explanation: We use "that" when talking about the car because it is an object, not a person.
Incorrect: The woman that was driving the car was wearing a blue shirt.
Correct: The woman who was driving the car was wearing a blue shirt.
Explanation: Although the first sentence could is not completely incorrect, "who" is preferred when referencing a person.
