The Boolean expression $A \oplus B \oplus A$ is equivalent to

GATE · 1987 · CS · Descriptive B

1. A.

   $AB + \overline {A}\;\;\overline B$

2. B.

   $\overline{A}\;B+A\;\overline{B}$

3. C.

   $B$

4. D.

   $\overline{A}$

Attempted by 10 students.