While this might seem useful, it actually isn't. Knowing how soon each of the individual kinds of harm listed by Mark and Tina would reach its maximum level doesn't actually help us compare the levels of harm from each type of cup. For example, knowing that methane released from paper cups will peak sooner than styrene from foam cups doesn't help us decide if methane or styrene is more harmful, let alone how all the other effects of foam versus paper cups factor into overall environmental damage. So this doesn't decide the issue.

Irrelevant. Mark and Tina are just comparing the pros and cons of two kinds of disposable goods. Whether different societies use different levels of those goods doesn't relate to their arguments.

Incorrect. This might seem like a sensible way to solve the problem of "disposable goods" in general — if both paper and foam cups are bad, let's find another alternative — but we don't have that option for this stimulus. Remember that we're trying to decide between Mark and Tina's arguments, and each of them is picking a side between foam or paper cups.

So regardless of whether a third alternative is available, we're interested in the question of whether foam is preferable to paper or vice-versa. We're not claiming that either one of the two is the "best" option, just trying to decide which one is less harmful than, and so preferable to, the other.

This is correct. If a significant amount of the harm caused by both these types of cups is just a result of bad production, transportation, or disposal methods, rather than inherent to the cups and their materials, then it's possible the "actual" harm caused by the two types of cups could be very different than what either Mark or Tina is saying. Much of this harm could be reduced by more efficient uses of energy, transportation, etc.

So to get an accurate sense of which type of cup is more preferable or harmful, this would be very useful information to know. Notice that while this doesn't give us a direct answer as to whether Mark or Tina is correct, it does give us important information that lets us "recalibrate" the scale of the damage they both mention, and then potentially decide whether foam or paper cups are more harmful, based on more relevant data.

Irrelevant. Neither Mark nor Tina is interested in the capacity of these cups, which is a consumer-side consideration. They're interested in the environmental effects of the cups as produced, transported, and disposed of.