The author' s attitude towards the three patterns of behavior mentioned in the passage is best described as one of ______.

A．they migrate for part of each year
B．they spend less time contributing to family income
C．they spend more months on school
D．their parents sometimes work at jobs other than farming

A．A Survey of Three Mexican American Families at Work in Texas.
B．Innovative Career Women: Effects on Family Unity.
C．Changes in the Life Styles of Migrant Mexican American Families.
D．Farming of Family: The Unavoidable Choice for Migrant Farm Workers.