Here are the correct answers to fill in the blanks:

(5) **C. recycling**
(6) **A. possible**
(7) **C. whenever**
(8) **A. to do**
(9) **C. to take**
(10) **A. so that**

So the complete sentences would read:

We should put objectives that we can recycle in **recycling** bins. Secondly, instead of talking our car wherever we go, we ought to leave it at home **possible**, and go on foot or **whenever** public transport. When we have to drive to the market **to do** shopping, we should always remember **to take** our own bags **so that** we don’t need to use the supermarket's plastic bags.