As is, 2 sign changes in ++-++, so 0 or 2 positive real roots.
With odd degree signs reversed, 2 sign changes in +---+, so 0 or 2 negative real roots.
The last selection is the correct choice based on the rule of signs.
Positive Real: 2 or 0
Negative Real: 2 or 0
Complex: 4, 2, or 0
_____
A graph shows there are actually 2 negative real roots and 2 complex roots.
