In the project of IEEE-754 to define 64 -bit we require a REAL8 double precision that is equal to 8 bytes and 64 bit, and it is also used for floating-point arithmetic, and other options were not correct that can be described as follows:
In option a, REAL4 is used to define 32-bit, that's why it is not correct.
In option c, This type of declaration is not valid in IEEE, that's why it is wrong.
In option d, The REAL is a keyword that is used to define a value but in this, there is no value to define, that's why it is wrong.
