Answer:
opportunistic
Step-by-step explanation:
A person who is deemed to be opportunistic is thought to take opportunities that are presented to them regardless of their principles or previous stances on the said matter. The opportunistic people look up the circumstance and take the way that is best possible for themselves, using all the advantages they can. This adjective can often be tied to politicians or businessmen that are considered to be strategic.
Credulous is a person ready to believe anything as the truth. Disdainful means to show respect to someone. Proactive means the person is actively participating in the situation and readily working towards the goal.