To answer this question, we need to take into account that the population of a city decreases at a constant rate of 0.6% per year. This is constant, and we need to subtract this value to the total population to have the next year's population.
We also have that the percent can be written as follows:
n% = n/100
And we have that 0.6% is then 0.6% = 0.6/100 = 0.006.
Then, we have that the original population is p, and we need to subtract from it the 0.6% to have the next year's population. Thus, we have:
Therefore, the expression that represents next year's population is (1 - 0.006)p (option D.)