Which one of the following pairs is not correctly matched?

Relay cropping is a method of multiple cropping where one crop is seeded into a standing second crop well before the harvest of the second crop. e.g., sowing pulses in a rice crop before harvest.
Intercropping is growing two or more crops nearby. e.g., wheat after rice.
Multi-tier cropping is the pattern of growing two or more crops of different heights simultaneously on a piece of land. EG: coconut + pepper + pineapple + grass.
Sole cropping is the growing of a single type of crop on a piece of land. Eg: potato.