Every deed, mortgage, lease or other conveyance made in good faith by the guardian of a minor or individual adjudicated incompetent, pursuant to any order or judgment of a circuit court, made under the provisions of this chapter, shall be as valid and effectual as if made by the minor when of full age or by the individual adjudicated incompetent before the adjudication.
Wis. Stat. § 786.15
A conveyance of a ward's real property by a guardian acting pursuant to court order is binding upon the ward beyond the time of the latter's majority. An option is a "conveyance" within the meaning of this section. Clear View Estates, Inc. v. Veitch, 67 Wis. 2d 372, 227 N.W.2d 84 (1975).