If \( (\alpha \beta)(\delta \beta)=\gamma \gamma y \) such that \( \alpha, \beta, \delta, \gamma \) represent a number from 1 to 9 and are different digits and \( \alpha \beta, \delta \beta \) are two digit numbers and \( Yyy \) is three digit number and the trace of the matrix
\( A=\left[\begin{array}{llll}\alpha & 1 & 2 & 0 \\ 0 & \beta & 1 & 1 \\ 0 & 0 & \gamma & 3 \\ 1 & 1 & 0 & \delta\end{array}\right] \) is a, then \( \frac{a}{7}= \)
a. 21
b. 7
c. 3
d. none of these
