Application of Derivatives - Leigh

[zxfmontreal]

CFAI online assessment, question 2, why duration of -3.625 (swap C) is used as the duration of swap? I actually calculated the average duration of swaps A, B and C…
Anyone knows why?

 

[cpk123]

higher duration = lower nominal ….
in the absence of full question

 

[derswap07]

I just did it. Usually lower the NP it is better. But the answer does not give any other notional-except one. So even if you calculate all of them- only one will match the answer.