设f（x）是定义在（-∞，+∞）上的连续函数，则（）．<br>A:<img src="/Image1/dc/dc788551cd975ab11c33a219a6549a9e.jpg" />必收敛<br>B:当时<img src="/Image1/3d/3d2d0bfda59d5d7b9ba71528dcc6086c.jpg" />，有<img src="/Image1/57/57bdea6fa2b04d84ef034797c8265791.jpg" />收敛<br>C:当<img src="/Image1/ce/ce2c02e652237f9250199314aaae01ae.jpg" />存在时，有<img src="/Image1/5e/5e0fda2d91326aa08621145a5570cef9.jpg" />收敛<br>D:当且仅当<img src="/Image1/00/00af2894aa98f1b0c20cdc6dbb7465f2.jpg" />均存在时，有<img src="/Image1/55/552ba68dca43509c92196f2201eef950.jpg" />收敛