Which phrases correctly state the causes of Repetitive Strain Injury? John is a marketing professional in New York City. His job includes regular travel. This month, John is busy preparing for a trade fair, for which he needs to work at his computer for long hours. Lately, John has also begun skipping lunch. He keeps busy emailing invitations to his customers, and checking if all products are ready for display in the trade fair. After a few weeks of tireless work, John develops headaches and feels numbness in his fingers. John’s friend suggested that John has developed RSI due to poor posture at work and lack of sleep. John is now taking medication and following ergonomic principles to get rid of his pain and discomfort.