I can't say which wine is best-it's a ____ of personal taste A affair B event C matter D variety但不懂

I can't say which wine is best-it's a ____ of personal taste A affair B event C matter D variety但不懂
I can't say which wine is best-it's a ____ of personal taste A affair B event C matter D variety
但不懂

I can't say which wine is best-it's a ____ of personal taste A affair B event C matter D variety但不懂
选择C
解析：it is a matter of...是固定句型,意思为：“这是一个…的问题”
翻译为：我不能说哪种酒是最好的——这是一个人的个人品味问题.
对你有所帮助的话,

a matter of表示...的事情「问题所在」＂这是个人口味的问题＂
以前学过as a matter of fact的吧 事实上的问题所在

a matter of...固定词组，有关于xxx的
举例：as a matter of fact，事实上
在这里，意思是：我不知道哪种酒是最好的，这跟个人口味有关。
其他选项均不能构成该词组。