[Guess What] Comprehensive, Boring F Grade

Unified Level B Guessing Game No. 1: A family went looking for a rental. There were three people in the family: a couple and a 5-year-old child. They saw a rental advertisement and hurried over. The apartment was nice, but the landlord said, 'I don't rent my apartment to tenants with children.' The couple was very disappointed and walked away. The 5-year-old child saw everything, went back, and knocked on the landlord's door. After the door opened, the child said something that made the landlord laugh out loud and decide to rent the apartment to them. What did the 5-year-old child say to finally persuade the landlord? No. 2: From which place on Earth, no matter where you go, is it always south? Unified Level A No. 3: There is a famous psychological phenomenon in the world! When you are watching TV and reach a climax, suddenly an ad plays. Even though you know it's a trick by advertisers, you still can't help but keep watching. What phenomenon is this? NC Question F-Level Guessing Game! No. 4: A 60-year-old man married a 70-year-old woman, and it turned out she was still a virgin! Who is this old woman? PS: Boring, my comprehensive B hasn't been featured yet? Where did the moderator go?