If attribute A determines both attributes B and C, then it is also true that:

Option1: A ? B.
This option states that attribute A determines attribute B. In the given scenario where attribute A determines both attributes B and C, this statement is true.

Option2: B ? A.
This option states that attribute B determines attribute A. However, in the given scenario where attribute A determines both attributes B and C, this statement is not necessarily true.

Option3: C ? A.
This option states that attribute C determines attribute A. In the given scenario where attribute A determines both attributes B and C, this statement is not necessarily true.

Option4: (B,C) ? A.
This option states that attributes B and C together determine attribute A. In the given scenario where attribute A determines both attributes B and C, this statement is not necessarily true.

Therefore, the correct option is Option1: A ? B.