21. Mobile service \( X \) offers unlimited phone minutes for \( \$ 45 \) per month when you buy a new phone at
\( \$ 155 . \) Service \( Y \) charges \( \$ 135 \) per quarter, but offers a phone for \( \$ 65 . \) After how many months will a user have paid the same total to either service? A) \( 1 \) B) \( 3 \) C) \( 8 \) D) The totals will never be equal.