It would be the best to choose as recommenders people with whom you have spent the maximum time.
Such people will have the most to say about you and the colleges will want to believe them, since they know you best.
Based upon your post, I would suggest you take the recommendation from people with whom you have atleast 2 years work collaboration.
Mix and match them to include work capailites and those of extra-curricular work or hobbies.
I would suggest you not to include people with whom your exposure was just 3 months when you have better recommendors available
Please press KUDOS if my post helped !!