Answer:
C. Slide A, plant cells; Slide B, animal cells
Explanation:
The slide A has some organelles that are unique to plant cells, and are mostly found in plant cells. Organelles such as a cell wall and chloroplasts are unique features of plant cells. They are normally absent in animal cells.
Therefore, slide A, which has these cell organelles can be rightly labelled as "plant cells", while side B, which has these organelles missing, can be labelled as "animal cells".