Three statements are given followed by Three conclusions numbered I, II & III.
Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follow(s) from the statements.

Statements:
Some doctors are tigers.
All tigers are umbrellas.
Some umbrellas are buses.

Conclusions:
I. Some doctors are umbrellas.
II. Some tigers are umbrellas.
III. Some buses are umbrellas.