Answer:
Political parties can use voter-data management systems to tailor their policies to fit their constituents best and maximize voter turnout.
That's how politicians interact with the voters.
"...Politicians and their campaigns use these lists to perceive the electorate".
Population growth is encouraged in developed countries, while developing countries are actually encouraging limiting population growth.
Developed countries face the problem of aging populations - more people on pensions, less people working and encouraging having more children is supposed to counter this. - the best answer is D.
If you’re talking about supply and demand, demand is how much people want of something, and the suppliers how much of it is available. If there is more demand then there is supply, the price of the product will go up. If there is more supplied and there is demand, the price will go down.