According to the passage, a thermal carafe is necessary when the coffee is ______.

A．People used to drink coffee in larger quantities.
B．It is essential to attach a separate carafe, while "drip" coffee makers are applied.
C．People used to make a pot of coffee in the morning and drink it up.
D．The new coffee makers usually cost less than before.

A．The speculations of Thales.
B．The forces of electricity, magnetism, land gravity.
C．Aristotle's natural science.
D．Galileo's discoveries.