judging by（或 from）意思是“从......来看”、“据......来判断”，可用来引导独立分句（其逻辑主语不一定与主句的主语一致）。例如：Judging from his look, he may be sick. 从他的外表看，他或许生病了。/ Judging by his accent, he must be from Guangdong. 听他的口音，他准是广东人。/ Judging from what you say, she ought to succeed. 从你说的情况来看，她应当能成功。

      注：to judge by（或 from）与 judging by（或 from）的意思和用法相同。例如：To judge by the villas he owns, he must be very rich. 从他拥有的别墅看，他一定很富裕。/ To judge from the evidence of the coroner, the deceased was still alive at five o'clock.  从验尸官提供的证据看，死者在5点钟时还活着。

     （以上摘自《薄冰英语惯用法词典》）

      所以，我认为 C. Judging from   D. To judge from 都正确。

Judging from what you said, 为现在分词短语作评注性状语。非谓语动词作评注性状语，其逻辑主语为说话人。说话人与judge这个动作为主动关系，所以要用现在分词，不能用过去分词。judge的动作略先于后面的句子，表示原因，所以用现在分词而不用不定式。不定式作评注性状语带有目的意义，例如to begin with, to tell you the truth. 这里并没有目的意义，所以不用不定式。