Stagflation:

a.

occurs every ten to fifteen years.

c.

is defined as stagnant growth combined with deflation.

b.

only occurs at full employment.

d.

is defined as stagnant growth combined with inflation

Stagflation is defined as stagnant growth combines with inflation. The correct option among all the options that are given in the question is the last option or option "d". It is a term that is used in economics to show the state of stagnation and inflation. During this stage, unemployment remains very high and growth rate slows down drastically.