In a first order reaction, the time required to reduce the concentration of reactant from 1 mole/litre to 0.5 mole/litre will be __________ that required to reduce it from 10 moles/litre to 5 moles/litre in the same volume.

• A. more than
• B. less than
• C. same as
• D. data insufficient; can't be predicted.