Answer:
(a) A/B refers to the set of elements that are in A but not in B. So, A/B = {1, 6, 8}
(b) B/A refers to the set of elements that are in B but not in A. So, B/A = {2, 5, 7}
(c) A/C refers to the set of elements that are in A but not in C. So, A/C = {3, 4, 8}
(d) C/A refers to the set of elements that are in C but not in A. So, C/A = {2, 9, 10}
Note: It's important to clarify what the "/" symbol means in set theory, which is the set difference operator. It represents the elements that are in the first set but not in the second set.