Given f(x) = x³+ 3 x²– 4 x – 12, which of the following statement below best describes its graph?
A. The graph is shaped like a letter “U” with its sides sloping upward.
B. The graph is shaped like a letter “U” with its sides sloping downward.
C. A curve line which goes down to the far left and up to the far right.
D. A curve line which goes up to the far left and down to the far right.​