The answer is D. Assessment is appropriate for infants and toddlers. It's actually recommended. Screenings of the children is not going to document their growth. There is technically a reliable way. And recording developmental milestones like their first word and when they start walking, crawling and running is extremely crucial in a child's learning process.
If you conserve or save scarce resources they will no longer be as scarce as before and more of those scarce resources will be available. Conservation can even make the scarcity of a resource nonexistent, meaning the resource is now plentiful or enough.