Thor entered into a contract with Loki whereby the latter will construct Thor's house for a service fee of P5,000,000. Subsequently, Loki changed the terms, and asked Thor to pay P6,000,000, citing unforeseen challenges in accomplishing the house. Thor presented two medical certificates citing that two out of her five workers got sick, and he was forced to hire another personnel and pay higher wages. Is Loki's action of asking P6,000,000 from Thor justified?

A. No. It violates the mutuality of contracts.

B. Yes. This is in consonance with the autonomy of contracts.

C. Yes. This is a form of novation of obligation.

D. No because Thor was not informed beforehand.