Step 1: Rank potency from broadest to narrowest.
Stem cell potency runs on a scale: totipotent can build an entire organism plus supporting tissue, pluripotent can build almost every cell type in the body but not a whole organism, multipotent can build a limited group of related cell types, and unipotent can only build one specific cell type.
Step 2: Place the zygote and embryonic stem cells on this scale.
A fertilized egg is totipotent. Inner cell mass cells of an early embryo are pluripotent. Neither of these describes stem cells found in an adult.
Step 3: Place adult stem cells on the same scale.
Adult stem cells, such as those in bone marrow, have already narrowed their potential. They can still make several related cell types, for example the different blood cell lines from one bone marrow stem cell, but they cannot make unrelated tissue types like nerve or muscle.
Step 4: Match this behavior to the correct term.
Making several related but not all cell types is exactly the definition of multipotent, sitting between pluripotent and unipotent on the scale.
Final Answer:
Adult stem cells are mostly multipotent, option (3).