What Trend,related to a Decline in Social Capital,did Robert Putnam

Multiple Choice

What trend,related to a decline in social capital,did Robert Putnam focus on in his book Bowling Alone?

A) the decline in donations to charitable organizations in the United States
B) the decline in beer drinking among "lone" bowlers
C) the declining interest in global capital investments
D) the declining interest in community-based activities and organizations