The sole proposal for a defunct Knoxville high school came from a group with charter school credentials.

In January, Knox County started accepting proposals for the old Rule High School, which closed in 1991.

RELATED: Knox Co. seeking proposals for deteriorating Rule High School

By the proposal deadline of 2 p.m. Thursday, only one had come in.

Rule K-12 Charter School Group made the lone bid. It's comprised of three entities: American Charter Development and Finance, Architects Weeks Ambrose McDonald and Knoxville non-profit organization Genesis Rock.

American Charter Development is a Utah-based charter school developer. According to its website, "ACD provides its services with no upfront cost to the school, and meets the financial obligations required to deliver a fully-functional, customized charter facility to our client-partners."

Architects Weeks Ambrose McDonald is a Knoxville architectural firm with an impressive array of regional designs, including the Haslam Business Building and Ayres Hall on UT campus, several local high schools and middle schools and a major addition and renovation to the UT Medical Center, to name just a few.

Genesis Rock is a Knoxville non-profit organization that has made several unsuccessful attempts at opening a local charter school, often called the Dream Academy.

Knox County is barred from revealing the contents of the group's proposal. It could only tell WBIR 10News who submitted it.

Charter Schools - and the state-funded vouchers to pay for them - have been a hot-button item this year, as President Trump nominated for his Education Secretary Betsy DeVos, an advocate of charter schools.

Proponents say charter schools and vouchers give low-income students access to better schools.

Critics say charter schools take money away from public schools and give it to privately run charter schools.