Let A={0,1,4,7}. Are the following relations on A symmetric? 1. {(7,4),(1,1),(4;4),(4,7),(0,0),(7,7)} 2. {(7,0),(0,0),(1,4),(4,1),(1,7),(0,7),(7,1)} 3. {(0,1),(7,7),(0,0),(7,0),(4,4),(1,0)} 4. {(7,0),(4,4),(1,1),(1,4), (0,0),(1,7)} 5. {(4,4),(0,4),(0,0),(4,7),(4,0)} 6. {(0,0),(4,4),(7,7),(1,1)}.