The odd one out is A, cot. Cot is a small bed, while the others are all items that are used on a bed.
A cot is a small bed, typically for a child or a guest. It is usually made of metal or wood, and has a simple frame with a mattress and sheets. Cots are often used in dormitories, hospitals, and other places where people need to sleep in a temporary or shared space.
A sheet is a piece of fabric that is used to cover a bed. It is usually made of cotton or linen, and is often white or another light color. Sheets are typically fitted to the mattress, and they can be either flat or fitted. Flat sheets are the most common type, and they are simply placed over the mattress. Fitted sheets have elastic bands around the edges, which help them to stay in place on the mattress.
A quilt is a bed covering that is made of two layers of fabric that are sewn together with a layer of batting in between. Quilts are often decorated with patterns, and they can be made from a variety of materials, including cotton, wool, and silk. Quilts are typically used in the winter to keep people warm, but they can also be used year-round.
A pillow is a soft cushion that is used to support the head and neck when sleeping. Pillows are typically made of feathers, down, or foam, and they can be filled with a variety of materials, including cotton, wool, and silk. Pillows are often used in conjunction with a mattress and sheets to create a comfortable sleeping environment.
A blanket is a piece of fabric that is used to cover the body for warmth. Blankets are typically made of wool, cotton, or flannel, and they can be either solid or patterned. Blankets are often used in the winter to keep people warm, but they can also be used year-round.