Correct answer: (B) All three are band-pass filters.
Explanation
Each plot has zeros at z=+1 and z=−1. These locations correspond to ω=0 and ω=π, so each response rejects both DC and the highest discrete-time frequency.
Their nonzero intermediate-frequency response gives the intended **band-pass classification, B**. The different poles shape the passband, rather than changing those endpoint zeros.
**Source qualification:** R has poles on the unit circle at ±j. It is an ideal resonant limiting case and is not BIBO stable; the classification does not imply a realizable stable filter at those exact pole locations.
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