This is a parabola which looks like an inverted U. Its will have a maximum value when t = 7 as we see from the vertex form below:-
- t^2 + 14t - 40
= - ( t - 7)^2 + 49 - 40
= -(t - 7)^2 + 9
There is an axis of symmetry at x = 7.
so a is true since 7 is the maximum value of the function and its less at t = 6.
c is also true because of the symmetry about t = 7
