Which of the following statements about subscreens are correct?

a. You call subscreens using the screen command CALL SUBSCREEN

b. You call subscreens using the ABAP command CALL SUBSCREEN

c. The statement LEAVE TO SCREEN is allowed in subscreen flow logic

d. Subscreen have their own OK code field.

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Which of the following statements about pushbuttons are correct?

a. on a screen always have a corresponding function key

b. in an application toolbar always have a corresponding function key

c. with function code E cause program termination

d. in an application toolbar always have a function code

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