Use Descartes' Rule of Signs to Determine the Possible Number $f ( x ) = x ^ { 5 } + 2 x$

Multiple Choice

Use Descartes' Rule of Signs to determine the possible number of positive and nega- tive zeros of $f ( x ) = x ^ { 5 } + 2 x$

A) 1 positive real; 3 negative reals or 1 negative real
B) no positive reals; no negative reals
C) 1 positive real; 5 negative reals or 3 negative reals or 1 negative real
D) 5 positive reals or 3 positive reals or 1 positive real; no negative reals
E) 3 positive reals or 1 positive real; 3 negative reals or 1 negative real