Let us discuss this perfect progressive, it shows that an action started within the past and has continued to this moment. this perfect continuous usually emphasizes duration, or the quantity of your time that an action has been happening
It is formed by using – has/have + been + participle baseverb+−ing
So, by this discussion we will say that the right solution is given within the option – b – has/have been + the current participle baseverb+−ing.
The other options are incorrect because they are doing not share the needed rule to be perfective tense progressive.

The perfect progressive tense, also known as the perfect continuous tense, is used to indicate that an action or event is, was, or will continue to occur (progressively), but that it will end or pertain to a later time (perfect).