There are two answers: E or D.

Given B is in the middle of the ladder. So there are 3 persons higher than B and 3 are lower than B.

Given G is in between A and B. So A < G < B. or, B < G < A.

given E is in between B and F. So B < E < F or, F < E < B.

given F is in between E and D, so E < F < D or D < F < E

Given E < A < C

If we choose, A < G < B, then E < A < G < B. ie., 3 persons lower than B.

* The person E is on the lowest step.*

Hence, the remaining C , D and F are above B. Hence, we choose, B < E < F. Since, E < F then we choose E < F < D. So B < E < F < D.

So the order is E < A < G < B < E < F < D.

======================================

There is a second solution.

given E < A < C.

Now, suppose we choose, B < G < A.

Then B < G < A < C. Hence, D, E and F are below B.

So we choose, F < E < B and D < F< E.

*Thus the order is : D < F < E < B < G < A < C *

hence, the person D is on the bottom step of the ladder.