OG详解-OG1 数学2 Q16

Choice B is correct. For a quadratic function defined by an equation of the form g (x)= a (x -h)² + k , where a , h, and k are constants and a > 0, the minimum value of the function is k. In the given function, a = 1, h = 0, and k = 55. Therefore, the minimum value of the given function is 55.
Choice A is incorrect. This is the value of x  for which the given function reaches its minimum value, not the minimum value of the function. Choice C is incorrect and may result from conceptual or calculation errors. Choice D is incorrect and may result from conceptual or calculation errors.