Which of the following statements is false?

a. A lambda that receives two ints, x and y, and returns their sum is
(int x, int y) -> {return x + y;}
b. A lambda’s parameter types may be omitted, as in:
(x, y) -> {return x + y;}
in which case, the parameter and return types are set to the lambda's default type.
c. A lambda with a one-expression body can be written as:
(x, y) -> x + y
In this case, the expression’s value is implicitly returned.
d. When a lambda's parameter list contains only one parameter, the parentheses may be omitted, as in:
value -> System.out.printf("%d ", value)

b. A lambda’s parameter types may be omitted, as in:
(x, y) -> {return x + y;}
in which case, the parameter and return types are set to the lambda's default type.
Actually, the parameter and return types are determined by the lambda’s context.