Which of the following is not a valid SQL statement?
a. CREATE TABLE anothernewtable (newtableid VARCHAR2(2));
b. CREATE TABLE anothernewtable (date, anotherdate) AS (SELECT orderdate, shipdate FROM orders);

c. CREATE TABLE anothernewtable (firstdate, seconddate) AS (SELECT orderdate, shipdate FROM orders);

d. All of the above are valid statements.