The food source that is produced during photosynthesis is

A cause or starting point the source of a rumor. 2 : the beginning of a stream of water the source of the Nile River. 3 : someone or something that supplies information a reference source. 4 : someone or something that provides what is needed a source of supplies a source of strength.

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.