The straight lines `I_(1),I_(2),I_(3)` are paralled and lie in the same plane. A total number of m point are taken on `I_(1),n` points on `I_(2)`, k points on `I_(3)`. The maximum number of triangles formed with vertices at these points are
A. `""^(m+n+k)C_(3)`
B. `""^(m+n+k)C_(3)-""^(m)C_(3)-""^(n)C_(3)-""^(k)C_(3)`
C. `""^(m)C_(3)+""^(n)C_(3)+""^(k)C_(3)`
D. none of these
