Yes they can be seen using a light microscope.... hope this helps! :)
The answer I would go with would be 3. Dispose according to your teacher's instructions. Hope this helps you out.
It can be observed that from the given choices, only two are from the group IA and the other two is from the group 7. Those belonging to group IA are the lithium (Li) and Potassium (K). The other two are from group 7. These are bromine (Br) and Iodine (I). Thus, the answer to the question are letters B and D.
