A country that has been relatively poor is starting to become wealthier. This has brought many people into the capital city, causing the population to grow very rapidly. Many new apartment buildings, as well as water and waste management systems, are being constructed to meet their living needs. Which other technology would most directly help the survival of such an expanding population?

A.
Using space in the city to build new landfills

B.
A method for growing food with less available land

C.
Access to modern transportation systems

D.
Building more parks and open spaces for recreation