The correct options are
A shall, will
C will, will
Modal verbs help determine the mood of a sentence, to indicate obligation, permission, possibility and so on. In the given sentence, a future action is referred to, "practicing yoga tomorrow". From the given options, 'shall, will' is the most suitable; 'shall' is used in the first person and 'will' is used in the second or third person, to provide information about a future action. In this sentence, shall is used in the first person "I" and 'will' in the second person "you", hence option A is correct. In modern English, 'will' is being used more frequently in the first person, to indicate a future action, hence 'will' is also the correct option for "I", and option C is also correct. 'Will' is used for all persons now, but when 'shall' is used in the second and third person, it expresses a command or a threat; hence when placed before "you" it indicates a command (which isn't the case). Hence option B is incorrect. 'Should' is used as the past tense of 'shall' in Indirect speech, but the given sentence is in Direct speech; hence 'should' is not the right modal for "I" and option D is incorrect.