a. It is OK to assign 1, 2, 3 to an array of Integer objects in JDK 1.5.
b. It is OK to automatically convert an Integer object to an int value in Line 2.
c. It is OK to mix an int value with an Integer object in an expression in Line 3.
d. Line 4 is OK. An int value from intArray[0] object is assigned to a double variable d.