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Explanation:

Given, an + 1 = 11+1an

⇒ a1 = 1

⇒ a2 =  11+1a1 = 12

⇒ a3 =  11+1a2 = 13
...
⇒ an =  1n

Now: a1 a+ a2 a+ a3 a+ ... + a2008 a2009  = 11×2 + 12×3 + 13×4 + ... + 12008×2009

11-12 + 12-13 + 13-14 + ... + 12008-12009

11-12009 = 20082009

Hence, option (c).

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