Directions: Read the following passages and choose the best answers to the questions.
At sixteen Ron Mackie might have stayed at school, but the future called to him excitedly. "Get out of the classroom into a job," it said, and Ron obeyed. His father, supporting the decision, found a place for him in a supermarket. "You’re lucky, Ron," he said. "For every boy with a job these days, there’s a dozen without." So Ron joined the working world at twenty pounds a week.
For a year he spent his days filling shelves with tins of food. By the end of that time he was looking back on his school-days as a time of great variety (多样性) and satisfaction. He searched for an interest in his work, with little success.
One fine day instead of going to work Ron got a lift on a lorry going south. With nine pounds in his pocket, a full heart and a great longing for the sea, he set out to make a better way for himself. That evening, in Bournemouth, he had a sandwich and a drink in a café run by an elderly man and his wife. Before he had finished the sandwich, the woman had taken him on for the rest of the summer, at twenty pounds a week, a room upstairs and three meals a day. The ease and speed of it rather took Ron’s breath away. At quiet times Ron had to check the old man’s arithmetic in the records of the business.
At the end of the season, he stayed on the coast. He was again surprised how straightforward it was for a boy of seventeen to make a living. He worked in shops mostly, but once he took a job in a hotel for three weeks. Late in October, he was taken on by the sick manager of a shoe shop. Ron soon found himself in charge there; He was the only one who could keep the books.Why did Ron Mackie leave school at sixteen

A. His father made him leave.
B. He had reached the age when he had to leave.
C. He left because he was worried about the future.
D. He left because he wanted to start working.