Write the range of the function \( f(x)=\cos [x] \), where \( -\frac{\pi}{2}x\frac{\pi}{2} \). (...

Write the range of the function \( f(x)=\cos [x] \), where \( -\frac{\pi}{2}x\frac{\pi}{2} \).
(a) \( \{1, \cos 1, \cos 2\} \)
(b) \( \{\cos 1, \cos 2\} \)
(c) \( \{1, \cos 2\} \)
(d) \( \{1, \cos 1\} \)