I believe that the second octagon is also regular. Then these two octagons are similar. The coefficient b of similarity is the ratio of their sides, i.e. b=21.8/10.9 = 2 (the second is twice larger linearly).
Then its area is b^2 = 4 times greater, i.e. 392.4 * 4 = 1569.6 (in^2). The answer is B.