It is not difficult to think about this problem carefully. In the title, the opposite of A is the same. If you do a lot of problems, it is easy to think of some elliptic and hyperbolic problems, but I think this problem is really unnecessary. Firstly, it is proved by mathematical induction that the perimeter of a triangle is constant. Then the triangle area has a Helen formula S = √ p (p-a) (p-b) (p-c), and p = (a+b+c)/2. Then p(p-a) is a constant value, (p-b) (p-c) = (a-b+c)/2 * (a+b-c)/2 = [a 2-(b-c)2]/4, then (b-c) 2. Topic: b [n+1]-c [n+1] = (c [n]-b [n])/2, so it is obvious that (b-c) 2 is getting smaller and smaller, so the area is getting bigger and bigger, so B is chosen.