Analyzing the given information:
- The organic compound contains oxygen.
- Upon oxidation, it forms a carboxylic acid as the only organic product.
- The molecular mass of the carboxylic acid is higher by 14 units compared to the original compound.

Reasoning:
- Oxygen-containing organic compounds can be classified into alcohols, aldehydes, ketones, and carboxylic acids.
- The given compound, upon oxidation, forms a carboxylic acid.
- The molecular mass of the carboxylic acid is higher by 14 units compared to the original compound.
- This increase in molecular mass is due to the addition of an oxygen atom (mass of oxygen = 16 units) during the oxidation process.

Applying the reasoning to the options:
Option A: Primary Alcohol
- Primary alcohols have the general formula R-CH2OH, where R is an organic group.
- Upon oxidation, primary alcohols form carboxylic acids.
- If the original compound is a primary alcohol, the molecular mass would increase by 16 units (mass of oxygen) due to the addition of an oxygen atom.
- However, the given information states that the molecular mass increases by 14 units, which is inconsistent with a primary alcohol.

Option B: Aldehyde
- Aldehydes have the general formula R-CHO, where R is an organic group.
- Upon oxidation, aldehydes can form carboxylic acids.
- If the original compound is an aldehyde, the molecular mass would increase by 16 units (mass of oxygen) due to the addition of an oxygen atom.
- However, the given information states that the molecular mass increases by 14 units, which is inconsistent with an aldehyde.

Option C: Secondary Alcohol
- Secondary alcohols have the general formula R-CHOH-R', where R and R' are organic groups.
- Upon oxidation, secondary alcohols can form ketones.
- If the original compound is a secondary alcohol, the molecular mass would remain the same upon oxidation, as no additional oxygen atom is added.
- Thus, a secondary alcohol is not consistent with the given information.

Option D: Ketone
- Ketones have the general formula R-CO-R', where R and R' are organic groups.
- Ketones cannot be directly oxidized to form carboxylic acids.
- Therefore, a ketone is not consistent with the given information.

Conclusion:
Among the given options, the only one consistent with the given information is option A: Primary Alcohol.