The correct answer is B. prone.
A soft-minded individual is easily influenced by others and is likely to believe things without evidence. This makes them more likely to embrace all kinds of superstitions, which are beliefs that are not based on reason or evidence.
The other options are not as accurate. A soft-minded individual is not necessarily eager to embrace superstitions. They may be reluctant to do so, but they are more likely to do so than someone who is not soft-minded. A soft-minded individual is also not necessarily disposed to embrace superstitions. They may be disposed to believe things without evidence, but this does not mean that they are disposed to believe in superstitions specifically.
In conclusion, the correct answer is B. prone.