About Question enthuware.ocpjp.i.v11.2.3220 :

[teodorj]

Cannot use 'var' on variable without initializer. In other words, a var declaration must assign a value to the variable.

var also cannot be declare as instance field

[admin]

Enhanced explanation to include this point as well.
thank you for your feedback!

[goblingift]

Unfortunately, the description for the answer 1 "var s;" hasn´t enhanced yet.

It is still "Cannot use 'var' on variable without initializer. In other words, a var declaration must assign a value to the variable."
--> But should contains the comment, that var can´t be used for instance variables at all

[admin]

Where you are looking? I just checked the explanation and it is there.
Also, please update your question bank to v 1.53.