(单选题)

What is the difficulty confronting researchers of facial-recognition machines?

A.No computer is yet able to handle huge datasets of human faces.

B.There do not exist public databases with sufficient face samples.

C.There are no appropriate algorithms to process the face samples.

D.They have trouble converting face datasets into the right format.

参考答案：B

参考解析：

细节理解题。根据第七段第一、二句“...at least, not in formats that are accessible to academic researchers. Training sets like the ones Google and Facebook have are private.”可知，对研究者来说，问题不在于格式也不在于学术方面，而在于人脸图像样本集很多时候是私人的图片，而非公开的图片，比如谷歌和脸书上用户上传的图片。所以A项、C项、D项错误，排除。故选B。

知识点：阅读理解四选一英语专业基础知识阅读理解教师招聘-小学英语