听力原文： Venezuela. Thousands of oil workers have gone on strike to demand a pay increase. Union leaders say 90% of the country's 40,000 oil workers have stopped working. However, the Venezuelan oil industry officials say operations remain the same. They say it will be one week until the strike affects oil exports. The oil workers are demanding a 15% pay increase ordered for all government workers by President Hugo Chavez. The state-owned oil company says the presidential order does not include oil workers. Also Venezuelan school teachers went on strike demanding a similar pay increase.
Q: Why have Venezuelan oil workers gone on strike？
(21)

A. They demand a pay increase.
B. They want a hundred dollars.
C. They did not like their boss.