The pictures below show a bottle made of plastic and a block made of concrete.

Explanation :
The given picture shows a plastic bottle and a block made of concrete.
Minerals are the naturally occurring substance. All minerals have a specific chemical formula.
So, the statement that is correct about the plastic and the concrete is :
Both plastic and concrete are not minerals. This is because they are made by humans.
Plastics are produced by a process of polymerization or polycondensation process and cement is produced by mixing water, aggregate, and cement, etc.
Hence, the correct option is (b).