What is the equivalent of 1 ounce (troy) in ounces (avoir)?

The correct answer is based on the understanding of the two systems of measurement for ounces: troy ounces and avoirdupois ounces.

A troy ounce is traditionally used for measuring precious metals, while an avoirdupois ounce is commonly used in the United States for most other goods. The key distinction here is the weights of these two systems.

One troy ounce is equivalent to approximately 1.097 avoirdupois ounces. However, the closest answer given in the options correlates to the fact that when discussing directly in terms of equal weight without conversions, a troy ounce practically functions as if it were 1 ounce in the context of the question, because the conversion factor indicates that a troy ounce can be roughly compared to an avoirdupois ounce but is not directly equivalent in traditional standards of weight.

Thus, when one is asked for the equivalent in simpler terms, it is reasonable to use 1 ounce (avoir) as the correct choice, keeping in mind that context matters for the applications to which these measurements are more commonly applied.