Step 1: Understanding the Concept:
Combining ability is used in plant and animal breeding.
General and specific combining ability have different bases.
Step 2: Key Formula or Approach:
No specific formula.
Need to understand combining ability.
Step 3: Detailed Explanation:
General Combining Ability (GCA) is due to additive variance (A is correct).
Specific Combining Ability (SCA) is due to non-additive variance (D is correct).
Thus, A and D are correct.
B and C are incorrect.
Step 4: Final Answer:
A and D are correct.
Hence, the correct option is (C).