**Core Concept**
Gardner's Syndrome is a rare hereditary disorder characterized by the association of multiple colorectal adenomas, osteomas, and other soft tissue tumors, along with various extraintestinal manifestations. This condition is a subtype of Familial Adenomatous Polyposis (FAP), which is caused by mutations in the APC gene.

**Why the Correct Answer is Right**
Gardner's Syndrome is indeed a subtype of FAP, and it is characterized by the presence of multiple adenomas, osteomas, and soft tissue tumors. The condition is caused by germline mutations in the APC gene, which leads to the development of adenomas and other tumors. The APC gene plays a crucial role in regulating cell growth and differentiation, and mutations in this gene lead to uncontrolled cell proliferation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Gardner's Syndrome is indeed characterized by the presence of multiple osteomas, which are benign bone tumors. Osteomas are a hallmark feature of this condition.
**Option B:** This option is incorrect because Gardner's Syndrome is not typically associated with a family history of breast cancer. While there may be an increased risk of certain cancers in individuals with FAP, breast cancer is not a characteristic feature of Gardner's Syndrome.
**Option C:** This option is incorrect because Gardner's Syndrome is not typically associated with a family history of thyroid cancer. While there may be an increased risk of certain cancers in individuals with FAP, thyroid cancer is not a characteristic feature of Gardner's Syndrome.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that Gardner's Syndrome is a subtype of FAP, and it's characterized by the presence of multiple adenomas, osteomas, and soft tissue tumors. A key feature of this condition is the presence of multiple osteomas, which can occur in any bone but are most commonly found in the mandible.

**Correct Answer: A. This option is incorrect because Gardner's Syndrome is indeed characterized by the presence of multiple osteomas.**