Hello I need help with the following question, thank you for your help in advance

2. Define a language A fb, bc, da, cba, adc, bb, ac, bbc, cdc, A over the alphabet fa,b,c,d) a. Sort the strings in A in lexicographical order b. Define a binary relation R on A as ((xy) | xy is in A, and x and y contain a common non-empty prefix). Give two pairs of strings that belong to R and two pairs of strings not in R, where all strings in those pairs are in A. Determine whether R is an equivalent relation and explain why