Why is my 3-month-old kitten refusing to use the litter box?

There could be several reasons why your 3-month-old kitten is refusing to use the litter box. It could be due to a medical issue, stress, or a dislike of the litter type or box location. It's important to consult with a veterinarian to rule out any health problems and to observe your kitten's behavior for any signs of stress. Additionally, try experimenting with different types of litter and locations for the litter box to see if that helps encourage your kitten to use it.