フリー問題

問題文

Before the head unit is lifted, the engineer fits the supplied rail kit into the rack posts and then slides the chassis onto the rails. Why is the chassis carried on rails instead of resting on a shelf plate?

選択肢

1. Rails are used because the chassis stays visible while it slides outward, which matters every time the appliance is serviced later.
2. Rails are used because the chassis stays sealed while it moves outward, which matters every time the appliance is serviced later.
3. Rails are used because the chassis stays supported while it slides outward, which matters every time the appliance is serviced later.
4. Rails are used because the chassis stays cool while it moves outward, which matters every time the appliance is serviced later.