Two-Year-Old Daniel Begins Banging His Spoon on the Table

Two-year-old Daniel begins banging his spoon on the table. Two-year-old Elaine joins in and bangs her spoon on the table. Daniel responds by banging his spoon again, and Elaine then bangs her spoon some more. This episode suggests that

A) both Daniel and Elaine probably have the ability to recognize themselves in the mirror.
B) Daniel and Elaine must have some understanding of each other's intentions and behaviour.
C) Daniel and Elaine must have some degree of self- and other-awareness.
D) All of the alternatives are correct.