Read the passage describing the famine that struck Ireland in 1740 to 1741. In 1740–1741 extremely cold temperatures struck vast areas of pre-industrial Europe, causing harvest failures that led to increased prices for staple food, famine, disease, excess mortality and migration. . . . Ireland was probably more vulnerable than most other European countries. Already in the first half of the eighteenth century, Irish food production was based heavily on potatoes and oats – a pattern of cultivation providing little resilience against the risk of harvest failure after an extremely cold winter. . . . Ireland was ill-prepared to deal with the consequences of harvest failure . . .

–The Irish Famine of 1740–1741,
S. Engler, et al.

Based on the passage, which best explains the cause of the famine?

lack of industry in Ireland
absence of farmers because of migration
over dependence on just two crops
mild winter weather