A: Abstract
B:body
c:conclusion


At the abstract it contains the Topic statement , contains sentences about what you are going to write in the body .
in another words say what you are going to say

in the body you support your ideas and give details about the topic sentence
i.e saying what you want to say.

conclusion it's a summary for the body
i.e confirm what you have said

There is another meaning for ABC writing strategy you will find it in the file below