Step 1: Understanding Sapinda Relationship.
Sapinda relationship refers to the relationship that prohibits marriages between certain degrees of kinship, specifically up to the 5th generation on the father's side and 3rd generation on the mother's side.
Step 2: Conclusion.
Therefore, the correct definition of a Sapinda relationship is between the 3rd generation (mother) and 5th generation (father), which makes option (B) the correct answer.