The correct options that apply to the differences between reflexive and non-reflexive verbs are:
A. Reflexive verbs indicate that the subject (the "do-er" of the action) is also the "receiver" of the action. D. Reflexive verbs includes a reflexive pronoun which must agree with the subject.
To clarify the other options:
B. This statement is not universally true, as not all reflexive verbs have a stem change in the specified forms. C. Reflexive pronouns typically come before the conjugated verb in Spanish, not after.
Thus, A and D are the correct answers.