How can this be achieved?

An Opportunity needs to have an amount rolled up from a custom object that is not in a master-detail relationship.

How can this be achieved?
A . Write a trigger on the child object and use a red-black tree sorting to sum the amount for all related child objects under the Opportunity.
B . Write a Process Builder that links the custom object to the Opportunity.
C . Write a trigger on the child object and use an aggregate function to sum the amount for all related child objects under the Opportunity
D . Use the Streaming API to create real-time roll-up summaries.

View Answer

Answer: C