According to the article, which economic event sparked the decade-long economic crisis?

A sudden rise in oil prices in 1973  sparked the decade-long economic crisis.

Explanation:

The decision to avoid selling oil to the U.S. as a result of the OPEC oil crisis

The ban was settled on 19 October 1973 by the twelve OPEC leaders. The oil prices increased in the next six months. Even when the blockade ended in March 1974, prices have continued to remain at higher levels.

In 1971 Nixon put a price ceiling on petroleum as oil demand rose and production decreased and foreign oil imports increased as sales were boosted at low prices. US crude oil shipments almost doubled from 1970 to 1973, exceeding 6.2 million each day in 1973.