According to their model, the minimum number of the species remaining, in thousands, multiplies by 10 every month. The researchers determine that right now, the population of crickets is at least 5 thousand. Once the minimum population reaches 1 million, measures are taken to stop the increase in population. If P represents the actual population of crickets in the town, in thousands, and t represents the time, in months, which of the following systems of inequalities can be used to determine the possible number of crickets in the town over time?