Based on Mendelian Inheritance,would It Be Necessary to Have Both

Based on Mendelian inheritance,would it be necessary to have both the genotype and phenotype for an organism when attempting to predict the inheritance pattern for a trait,such as hair color,in offspring?

A) Yes; individuals with different genotypes often have the same phenotype.
B) Yes; individuals with different phenotypes often have the same genotype.
C) No; knowing the phenotype will indicate the genotype.
D) No; knowing the genotype will indicate the phenotype.