To answer this question, we need to understand the rules and restrictions for declaring class-level (nonlocal) variables in Java.
Let's go through each option to understand why it is correct or incorrect:
Option A) protected int a;
This option is correct because there are no syntax errors or restrictions with declaring a protected class-level variable in Java.
Option B) transient int b = 3;
This option is correct because there are no syntax errors or restrictions with declaring a transient class-level variable in Java.
Option C) private synchronized int e;
This option is incorrect because it violates the rules for declaring class-level variables. In Java, the synchronized modifier is not allowed for class-level variables. It can only be used for instance-level methods or blocks.
Option D) volatile int d;
This option is correct because there are no syntax errors or restrictions with declaring a volatile class-level variable in Java.
Therefore, the correct answer is C) private synchronized int e. This option will not compile because the synchronized modifier is not allowed for class-level variables in Java.
Please select the most appropriate option.