Summary:
1. Taeyeon's father already got the information about the development beforehand and purchased the 864 pyeong using his daughter's name
2. He paid 3x the market price to B
3. Based on B's purchase, the land would doubled in price since in 2 years from this year
(The forest is in the vicinity, not the land B purchased)
4. As everyone knows, Taeyeon's land cannot be used for residential purposes
5. It is highly likely that they knew the development information in advance and purchased it
6. Seeing that land prices will double, it is hard to say that they are strictly victims