Which of the Designs Below Would Be Best Suited to ANCOVA

Which of the designs below would be best suited to ANCOVA?

A) Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group.The researcher was interested in the relationship between the therapist's ratings of improvement and stress levels over a 3-month treatment period.
B) Participants were allocated to one of two stress management therapy groups, or a waiting list control group based on their baseline levels of stress.The researcher was interested in investigating whether stress after the therapy was successful partialling out their baseline anxiety.
C) Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group.Their baseline levels of stress were measured before treatment, and again after 3 months of weekly therapy sessions.
D) Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group.Their levels of stress were measured and compared after 3 months of weekly therapy sessions.