I solve this question as shown below.Can you please help me to find the mistake

It is given L2 and L3 are langugages that are recursively enumerable but not recursive.

a) L2 - L1=L2

so recursively enumerable

b)L1 - L3=L1

so recursive. It means recursively enumerable also

c)L2∩L1 =empty (I don't know it is recursively enumerable or not)

d)L2 ∪L1 is recursively enumerable