Assume that the following statements are true.
A. If Sarah is drinking iced tea, then it is dinnertime.
B. If it is dinnertime, then Sam is drinking juice and nothing else.
C. If it is lunchtime, then Mario is drinking coffee and nothing else.
D. If it is breakfast time, then Rob is drinking water and nothing else.
E. Sarah is drinking iced tea.
Using only the information given above, determine if "Sam is drinking juice" must be true, may be true, or is not true. Explain your reasoning.