Final answer:
The standard addressing contingent gains in week 6 is IAS 37, which instructs not to recognize contingent gains until they are virtually certain.
Step-by-step explanation:
The standard that addresses what to do for contingent gains in week 6 is D) A: IAS 37, B: IAS 20; C: IFRS 9, D: IFRS 15. According to International Accounting Standards (IAS) 37 'Provisions, Contingent Liabilities and Contingent Assets', contingent gains are not recognized until it is virtually certain that the inflow of economic benefits will occur. When it arrives at contingent gains, this accounting standard demands prudence, avoiding the recognition of these gains until there is a high level of certainty that they will be realized.