Organizing a speech means to :

a)research the materials
b)presenting a speech in a logical manner
c)selecting words to use
d)adapt the speech to audience
my answer is d:))

No.

so it could be a)

Do you know the meaning of "organize?"

A speech that is organized is easy for the audience to listen

so its B right must me logical,because that is only way that the audience can understand us

Please read this definition of "organize."

http://www.merriam-webster.com/dictionary/organize

Which answer best fits this definition?

Actually, all of the answers are essential. For the most important one, follow Ms. Sue's advice.

hm,selecting words to use only this one

but to me make sense only B i don't know why :(

You are doing your audience a favor when you present ideas that flow well and logically and make sense