Which is the regular past pattern of Form X?

Ten Semantic Functions of Form X (Istifʿāl): Seeking, Suitability, Finding, Judging, Transformation, Adoption, Abbreviation, Response, Equivalence and Independent Use

• اِسْتَفْعَلَ
• اِفْتَعَلَ
• تَفَعَّلَ
• أَفْعَلَ