Rank the simple harmonic oscillators shown in the figure in order of their intrinsic frequencies, from highest to lowest. All the springs have identical spring constants, and all the blocks have identical masses.
a) $1,2,3,4=5$
b) $4=5,3,2,1$
c) $1,2,3=4,5$
d) 3,4,2,1,5
e) $3,2=5,4,1$