The graphs of $P(x) = x^4+c$ for $c= -1$, $0$, $1$, and $2$ are shown below.

For each curve, enter its value of $c$ (from the list above) which matches the letter of the graph:

Curve A:
Curve B:
Curve C:
Curve D:

For $P(x) = x^4+c$, increasing the value of $c$

A. moves the graph right
B. stretches the graph vertically
C. moves the graph up.
D. moves the graph down
E. stretches the graph horizontally