Find Only the Rational Zeros $$f ( x ) = x ^ { 4 } - 8 x ^ { 3 } + 4 x ^ { 2 } + 24 x - 21$$

Multiple Choice

Find only the rational zeros.
- $$f ( x ) = x ^ { 4 } - 8 x ^ { 3 } + 4 x ^ { 2 } + 24 x - 21$$

A) $- 7,1$
B) 7,1
C) $7 , - 1$
D) No rational zeros