The correct answer is A.
An inquisitive person is someone who is curious and eager to learn. They are always asking questions and seeking out new information. This type of person is more likely to gain proper knowledge than someone who is careless, indolent, dull, or uninterested.
A careless person is not paying attention to what they are doing or learning. They are not likely to remember what they have learned or to apply it to new situations.
An indolent person is lazy and does not want to put in the effort to learn. They are not likely to gain much knowledge, as they are not willing to put in the work.
A dull person is not intelligent and has difficulty learning new things. They are not likely to gain much knowledge, as they are not able to understand and retain information.
An uninterested person does not care about learning. They are not likely to gain much knowledge, as they are not motivated to learn.
In conclusion, only an inquisitive person can gain proper knowledge. They are the ones who are curious and eager to learn, and they are the ones who are willing to put in the effort to do so.