The most effective response to demonstrate how the use of third-person omniscient narration reflects the author's attitude toward marriage in "Pride and Prejudice" is by contrasting the reactions of Elizabeth and Mr. Collins.
This narrative style allows the reader to access the thoughts and feelings of both characters, highlighting Elizabeth's rejection of the marriage proposal due to her desire for love and compatibility, while Mr. Collins views the proposal as a practical and socially advantageous arrangement. This contrast illustrates the varying attitudes toward marriage during the time period and suggests Austen’s critical view of socially motivated unions, ultimately advocating for a marriage founded on mutual respect and affection.