The correct answer is D. prone.
A soft-minded individual is someone who is easily influenced or persuaded. They may be more likely to believe in superstitions because they are not as critical of information or as skeptical of claims. They may also be more likely to seek out information that confirms their beliefs, and to ignore or discount information that contradicts them.
The other options are not as accurate descriptions of a soft-minded individual. A disposed individual is someone who is inclined or willing to do something. An eager individual is someone who is enthusiastic or impatient to do something. A reluctant individual is someone who is hesitant or unwilling to do something.
It is important to note that not all soft-minded individuals are superstitious. However, those who are superstitious are more likely to be soft-minded.