Let s be the set of all values of e e [-x, t] for which the system of linear equations x + y + 3z = 0, -x + (tan 0)y + 7z = 0, x + y(tan 0)z = 0 has non-trivial solution. Then 120ee is equal to:
a) t - x
b) t + x
c) t * x
d) t / x