Final answer:
Cohabitation is proposed by Blackwell and Lichter to potentially lead to selection effects and lower marital commitment, which may contribute to higher divorce rates among cohabiting couples who marry.
Step-by-step explanation:
According to Blackwell and Lichter, a possible reason why cohabiting couples are more likely to get divorced if they marry is that cohabitation may lead to selection effects and lower marital commitment (answer choice d). Many couples view cohabitation as a trial run for marriage, and it's often seen as a pragmatic decision to save on living expenses or to spend more time together. However, cohabitation can lead to a later age for first-time marriage, as individuals may place a higher priority on education and career. Studies have found that those who cohabitate before marriage have a slightly higher rate of divorce than those who do not. A strong asset base is also reported to be a contributing factor to a lasting marriage, highlighting the importance of financial stability.