Montana mining co. (mmc) paid $200 million for the right to explore and extract rare metals from land owned by the state of montana. to obtain the rights, mmc agreed to restore the land to a suitable condition for other uses after its exploration and extraction activities. mmc incurred exploration and development costs of $60 million on the project.

mmc has a credit-adjusted risk free interest rate is 7%. it estimates the possible cash flows for restoring the land, three years after its extraction activities begin, as follows:

cash outflow probability
$10 million 60%
$30 million 40%

the asset retirement obligation (rounded) that should be recognized by mmc at the beginning of the extraction activities is:
a. $ 8.2 million.
b. $14.7 million.
c. $ 18 million.
d. $ 30 million.