Final answer:
When oxygen is removed from an air sample, the number of moles of water vapor decreases because oxygen is required to form water vapor; however, without specifics on reactions or conditions, detailed analysis is limited.
Step-by-step explanation:
When oxygen is removed from the initial air sample, the number of moles of water vapor removed would be option B) Decreases. This is because oxygen is a component of water (H2O), and removing oxygen from the environment would stop any subsequent water formation through combustion or other chemical reactions which produce water as a byproduct. This occurs because there are fewer oxygen molecules available to react with hydrogen to form water vapor. However, the question does not provide information on the reactions taking place or the conditions of the sample, such as temperature or pressure, which can affect the formation or presence of water vapor.