A household has $6 in wealth, which allocates between consumption and savings. The MB from consumption is $1.96, 1.45, 1.31. 1.21, 1.13 and 1.07 from the 1st, 2nd... unit of consumption C. If the interest rate is currently 0%, then the household's optimal consumption would be
a. 3
b. 4
c. 5
d. 6