What do the roman numerals in the pedigree diagram represent?

I think it is supposed to be generation so 1st and 2nd generation in this case.

Explanation:

Roman Numeral stands for the generation in the family

Explanation:

https://www.cs.cmu.edu/~genetics/units/instructions/instructions-PBA.pdf

Pedigree Analysis

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.