Coal mining is a dangerous and dirty job. Suppose someone developed new machinery that made coal mining safer and cleaner; at the same time, suppose it made coal miners more productive. We would expect that the wages of coal miners would

D. Rise, fall, or stay the same

Explanation:

In the case of a new invention, there are several scenarios that could play out. An invention which makes a job such as coal mining which was previously dangerous and dirty to become safer could result in;

1. A rise in the wages of the miners, perhaps, because their productivity is now increased.

2. A fall in the wages of the miners perhaps because they do not have to do much stressful work as there is now new machinery to make work easier.

3. Stay the same if the employer reasons that their wages are sufficient or commensurate to the work they now do.

answerindividual preferences are not revealed in the market for the good;

of the three mortgage options that demarco and tanya have to choose from, the balloon payment mortgage would be their best option, over adjustable payment and fixed payment plans.ultimately, the balloon payment plan would save demarco and tanya overall, in interest, would cost less monthly, and they would only have to make these payments for 8 years, opposing to 30 years for adjustable or fixed payment plans. 

overall, demarco and tanya would save $80,811 if they chose balloon payments over fixed payments, and would save $116,711 if they choose balloon payments over adjustable payments. benefits with choosing fixed payments over adjustable payments is that, in the end, the payments will still be $836.30 a month, while with adjustable payments, the initial monthly payments will be $763.38 to $1082.70 a month, ultimately leading to a more costly purchase. benefits with choosing fixed payments over balloon payments are not present. benefits in choosing adjustable payments over is that it has a lower interest rate, and starts with lower monthly payments initially. benefits in choosing adjustable payments over balloon payments include a lower interest rate, and lower initial monthly payments. benefits in choosing balloon payments over fixed payments include lower interest rates, lower overall price, lower monthly payments, takes less time to pay off, and does not require a downpayment. benefits in choosing balloon payments over adjustable payments include, lower monthly payments (when averaged), takes less time to pay off, and lower overall price.

hence, option c, balloon payments, is the best option for demarco and tanya to make this purchase, for it will save them a minimum of $80811, and a maximum of $116,711.