**Core Concept**
Carbohydrate antigens, also known as polysaccharide antigens, are a type of antigen that elicit an immune response. They are composed of repeating sugar molecules and are often found on the surface of bacteria and other microorganisms.

**Why the Correct Answer is Right**
Carbohydrate antigens typically do not induce a memory response, which is a hallmark of a T-cell-dependent immune response. This is because they do not require processing by antigen-presenting cells (APCs) and presentation to T-cells to stimulate a response. Instead, they directly stimulate B-cells, leading to the production of antibodies. This type of response is often referred to as a T-cell-independent response.

**Why Each Wrong Option is Incorrect**
**Option A:** Carbohydrate antigens actually have relatively high immunogenicity, meaning they are capable of inducing a strong immune response. This is because they can directly stimulate B-cells and induce the production of antibodies.
**Option C:** While carbohydrate antigens can stimulate B-cells, they do not typically cause polyclonal B-cell stimulation. Polyclonal stimulation refers to the activation of multiple B-cell clones, which is more characteristic of T-cell-dependent responses.
**Option D:** Carbohydrate antigens do not require stimulation by T-cells because they can directly stimulate B-cells. However, they can induce a response that is still dependent on the presence of certain co-stimulatory signals, such as CD40L, which is provided by T-cells.

**Clinical Pearl / High-Yield Fact**
It's worth noting that the immune response to carbohydrate antigens can be enhanced by the presence of T-cell-dependent co-stimulatory signals, such as CD40L. This is why some vaccines, such as the pneumococcal conjugate vaccine, use a T-cell-dependent adjuvant to enhance the immune response.

**✓ Correct Answer: B. Memory response is seen**