(A) 1 can normalized in floating point representation.
Ex:- 1 = 1 *20
(B)zero is not directly representable in the straight format, due to the assumption of a leading 1 (we'd need to specify a true zero mantissa to yield a value of zero)
(C)∞ is not directly representable in the straight format, due to the assumption of a leading 1 (we'd need to specify a true zero mantissa to yield a value of zero)
Hence,Option(d)b and c only should be the correct choice.