Here is a goal: How can you conserve your phone battery and make a low battery last longer?

Which way makes more sense to accomplish this goal?

Available options: 1). Put the phone in rice, this will conserve power, turning it off and on wastes more battery than setting it in rice. 2). Put the phone in airplane mode, this will conserve power, turning it off and on wastes more battery than setting it in airplane mode.
2).