I'll start you off.
For (a), I believe you can let be and let be .
For the above set:
a)Find an interpretation A of T ,with Domain the set |A|={a,b,c} ,which is model of T.In the interpretation at the constant a is assigned a, at the constant b is assigned b, at the constant c is assigned c.
b)Find an interpretation A of T ,with Domain the set |A|={a,b,c} ,which is NOT model of T.In the interpretation at the constant a is assigned a, at the constant b is assigned b,
at the constant c is assigned c. Moreover it must be a,b and b,c .
c)Find an interpretation of T ,with Domain the set | |={0} ,which is model of T.Find also an interpretation of T ,with Domain the set | |={0} ,which is NOT model of T. For it must be 0 .
Thank you..