Which of the following is a valid lambda expression?
B.
Option A is incorrect because the lambda expression is missing a semicolon (;) at the end of the return statement.
Option C is incorrect because the local variable test is used without being initialized.
Option D is also incorrect.
The parentheses are required on the left-hand side of the lambda expression when there is more than one value or a data type is specified.
Option B is the correct answer and the only valid lambda expression.