D: Build-up of troops. No peaceful country (or group) would need an army unless something big was about to happen
Employment opportunities increasingly lie in jobs requiring higher-level social or analytical skills, or both. Physical or manual skills, as much in demand as social or analytical skills some three decades ago, are fading in importance. Not coincidentally, employment is rising faster in jobs calling for greater preparation, whether through education, experience or other forms of training.
The answer is income because a person cannot buy a good without a physical means of purchasing the good.
Most iceberg warnings were ignored that day because the wireless operator was too busy sending out passenger messages via the Marconi wireless room. Plus the iceberg itself was very hard to see(black Ice)