Final answer:
The development of wheat as a staple crop in the British colonies is not a valid reason for the increased reliance on slave labor after 1680; the main crops were sugar, tobacco, and cotton.
Step-by-step explanation:
After 1680, there were several reasons for the increased reliance on slave labor in colonial America, but one of the options provided in the question does not align with these reasons. The development of wheat as a staple crop in the British colonies is not a correct reason for this increased reliance because the major cash crops utilizing slave labor were predominantly sugar, tobacco, and cotton. The other options representing valid reasons include higher wages in England reducing the number of emigrating servants, which made it difficult to fulfill labor demands through English indentured servants, planters' fear of the growing number of landless freemen in the colonies, and the British Royal African company losing its monopoly on the slave trade, which lessened restrictions and costs associated with the importation of slaves. Additionally, the American rush to cash in on the lucrative slave trade contributed to the growth of slavery in the colonies.