2. A campus sandwich shop has the following rules for making a good sandwich: (a) A sandwich must have at least one type of meat or lettuce, (b) A sandwich must have roast beef or lettuce, but not both, (c) If a sandwich has turkey or lettuce, then it must also have cheese. Write a simplified logical expression for the allowed combinations of sandwich ingredients using the following variables: c for a sandwich having) cheese; u for lettuce; h for ham; r for roast beef and t for turkey. Explain your answer briefly and indicate how you simplified it