The main purpose of Text I is to...

A warn professionals in the oil business about the frequent instability in oilfields. B criticize the strenuous working conditions oilfield operating teams are always submitted to. C provide useful advice to prospective workers intending to start a career in the oil industry. D inform the exact amount of experience a worker must have before looking for a job in an oil company. E encourage employees to look for a position in catering before applying for a job in offshore and overseas rigs.