When their baby was ready to head off to college, the beleaguered parents pulled out the college folder from their file cabinet and added up the cost of putting their first child through college from $1995-2000.$ The mother whimpered as she factored in the rising cost of tuition, fees, books, and inflation by multiplying the total by $2\mathrm{.}5.$ The father felt a searing pain go through his chest as he saw the total, knowing full well that their cost estimation approach, called:

Select one:

a$.$

Definitive estimation was highly accurate.

b$.$

An order of magnitude estimate was highly accurate.

c$.$

Feasibility estimation was highly accurate.

d$.$

Parametric estimation was highly accurate.