Which sentence is an example of faulty coordination?

a-farhad, a member of the debate team, is quite good at making his points of debate clear.
b-ryanne did not do well in the debate, even though she knew the topic well.
c-the members of the debate team are working hard and practicing often.
d-the debate team has many new members, and the team is not very good yet.

The correct answer of the given question above would be option D. The sentence that is an example of a faulty coordination is: The debate team has many new members, and the team is not very good yet. This sentence contains two complete main ideas, but are illogically connected since the first clause conveys a positive idea and the second conveys a negative one. Therefore, the correct coordination that should be used here is "but" instead of "and". The correct sentence would be: The debate team has many new members, but the team is not very good yet.