Given a relation and asked to enumerate all FD's and mark the trivial FD's
I suppose that in the exercise, the request “organize them accordingly to the LHS”, is just a request of sorting all the functional dependencies (maybe lexicographically) with respect first to the attributes of the left hand side (the determinant of the functional dependency) (and then maybe on the rigth hand side for all the FD with the same left part). 

For what concerns the list, I think it should include all the possible functional dependencies, including those with two attributes as determinant, as well as the (only) dependency with three attributes as determinant, as well as those with all the subset of attributes determined on the right part. So something like:

A -&gt; A
A -&gt; AB
A -&gt; AC
A -&gt; BC
A -&gt; ABC
AB -&gt; A
...
B -&gt; B
...


If you want to be super-formal, you can include also the trivial dependencies A -> {}, etc., as well as the trivial dependency {} -> {}.