Statement I: Sublimation is a process where a solid directly converts into vapor without passing through the liquid state. It is used to separate sublimable compounds from non-sublimable impurities. It is not specifically used for compounds based on having a low melting point, but rather based on their ability to sublime. Thus, Statement I is false.

Statement II: The boiling point of a liquid is the temperature at which its vapor pressure equals the external pressure. If the external pressure is reduced, the vapor pressure required to reach boiling is lower, which occurs at a lower temperature. Therefore, the boiling point decreases as the external pressure is reduced. Thus, Statement II is false.

Since both statements are false, the correct option is .