The following is the longitudinal characteristic equation for an F-89 flying at 20,000 feet at Mach 0.638. The Short Period natural frequency is .

hello your question is incomplete  attached below is the missing part  

answer : short period oscillations frequency  = 0.063 rad / sec

              phugoid oscillations natural frequency ( ) = 4.27 rad/sec

Explanation:

first we have to state the general form of the equation

=

where :

comparing the general form with the given equation

 = 18.2329

hence the short period oscillation frequency ( ) =  0.063 rad/sec

phugoid oscillations natural frequency ( ) = 4.27 rad/sec

correct it is c.) b b