From the given graph
a)
If the coefficient is positive, then the graph is upward
If the coefficient is negative, then the graph is downward
In the first 2 figures, the graphs are upward, then
A and B are positive
In the last 2 figures, the graphs are downward, then
C and D are negative
b)
The least coefficient is the coefficient of the graph which nearest to the x-axis
Since graph C is the nearest graph to the x-axis, but we have negative values, then
The least coefficient is the coefficient of the downward graph and farthest from the x-axis, then
D is the least coefficient
c)
The closest coefficient to zero is the graph C
