Answer:
d. Total assets of the current year.
Explanation:
All accounts of the current year regardless of their nature, what I mean with this is that any account could add or subtract, all that kind of operations at the end give you the total result of the current year, and every account of the respective year could be expressed as a percentage of the total assets of the respective year, for example:
Total assets year A $1000 Total assets year A 100%
cash year A $200 cash year A 20%
equipment year A $600 equipment year A 60%
buildings year A $200 buildings year A 20%
Every account correspond to the same year of the calculation.