The correct answer is: A. willing
A stubborn person is someone who is not easily persuaded or convinced to do something. They are often set in their ways and refuse to change their mind, even when presented with evidence that they are wrong.
A willing person, on the other hand, is someone who is happy to do something or who is easily persuaded to do something. They are often open to new ideas and are willing to change their mind when presented with new information.
The other options are not antonyms of stubborn.
A consenting person is someone who agrees to do something. They may or may not be willing to do it, but they have given their consent.
A pliable person is someone who is easily influenced or persuaded. They may not be stubborn, but they are not always set in their ways.
An easy person is someone who is not difficult to deal with. They may or may not be stubborn, but they are usually cooperative and agreeable.