Answer: The correct answer is- The offspring would be pink because of incomplete dominance.
Explanation-
Incomplete dominance produces a blend/ intermediate phenotype of both the parental phenotypes ( such as Pink in produced in this case) because none of the parental allele completely masks the effect of other.
As per the information given in the question, neither of the rose is dominant. This means that when both are cross bred, they will represent a heterozygous state ( when alleles for both the rose are present ), and they will produce an intermediate phenotype ( that is a blend of both the traits, which is pink).