Answer:
A is Key word
B is Key phrase
Explanation:
Keywords These are single, standalone terms which encapsulate the main ideas of your research topic. One example of this would be "architecture, accountancy, lawyers, etc"
Key phrase is a very specific combination of terms that represent standalone ideas which are expressed using more than one word. Often proper nouns, or well-known word combinations, these refer to distinct items, places, people, or ideas. One example would be "postmodern architecture."