The correct answer is option 'C) Conservatism'.

Explanation:
The fundamental accounting assumptions are the basic principles that guide the preparation and presentation of financial statements. These assumptions form the foundation of accounting and are generally accepted accounting principles (GAAP) that are followed by businesses worldwide. The three fundamental accounting assumptions are:

1) Going Concern Assumption: This assumption states that a business will continue to operate indefinitely, unless there is evidence to the contrary. It assumes that the business will not be liquidated in the near future and will be able to fulfill its obligations and continue its operations.

2) Consistency Assumption: This assumption requires that the same accounting methods and principles are consistently applied from one accounting period to another. It ensures comparability and allows users of financial statements to make meaningful comparisons over time.

3) Accrual Assumption: This assumption states that financial transactions are recorded when they occur, regardless of when the cash is received or paid. It recognizes revenues when they are earned and expenses when they are incurred, rather than when the cash is received or paid.

Conservatism, although an important concept in accounting, is not considered a fundamental accounting assumption. It is a principle that suggests that when there are uncertainties or doubts in accounting measurements, the accountant should choose the option that is least likely to overstate assets or income. In other words, it encourages the accountant to be cautious and conservative in recording financial transactions.

While conservatism is an important principle, it is not considered a fundamental accounting assumption because it is not universally applicable. Different accounting frameworks and jurisdictions may have different interpretations and applications of conservatism. Therefore, it does not have the same level of consensus and acceptance as the three fundamental accounting assumptions mentioned above.

In conclusion, the correct answer is option 'C) Conservatism' because it is not one of the fundamental accounting assumptions.