The piece from the bottom that should replace the question mark is the following:
Option B or second option
In this type of exercises, you have to search for the pattern that is followed in the two first lines to discover the third one.
A pattern is something that is repeated. It is something you can use as a guide.
The correct option is the second one, which could be described as:
x
x x
Check more information about sequence exercises here https://brainly.com/question/7631238