Which sentences explains the following equation? A. Two helium ions plus an oxygen ion from water.

B. two hydrogens atoms plus one air molecule from water.

C. two helium atoms plus on nitrogen atom form water.

D: Two hydrogen atoms plus one oxygen atom form water.

Mankiw attributes – chapter 1 and his 10 principles – differences in living standards within a countryover time and across countries at a moment in time to: a. the presence or absence of inflation and unemployment.b. the allocation of resources between private markets and the public sector.c. those that have dealt successfully with the efficiency v. equality tradeoff and those that haven’t.d. differences in productivity.e. ones that think at the margin and respond to incentives and those that don’t.