Is nuclear physics related to chemistry
?

Nuclear physics is related to chemistry in some way but it is rightly placed under the branch of physics.

Nuclear physics is the field of physics in which atomic nuclei are studied. As in chemistry reactions are studied, nuclear physics also studies the reactions of the atomic nuclei. Hence, in this way, these two fields might co-relate but there are more differences than similarities in the field of chemistry and nuclear physics.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.