甲地（0°、90°E）、乙地（60°N、 90°E）、丙地（0°、40°E）、丁地（60°S、40°W）与本初子午线的距离最近的是：

A．甲

B．乙

C．丙

D．丁

Clean water and fresh air are essential for our daily life, _______ we can't live.[ ]

A. by which

B. without which

C. that

D. on which