Respuesta :
7
I don't know how I would explain this, sorry.
Somebody else would probably be able to explain this better than me.
Answer:
C
Explanation:
Because If it is per shelf then to find the answer you need to use multiplication.
57 divided by 9 is 6 with 3 leftover so 6 shelves can hold 54 plants equally. But since there are still plants leftover you need one more extra shelf to hold the extra 3.