A
由题设知, A17 B17= 4×17+2 5×17−5= 7 8, 又 A17 B17= 17a9 17b9= a9 b9,所以 a9 b9= 7 8, 所以 a5+a13 b5+b13= 2a9 2b9= a9 b9= 7 8, 故选D.
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