213 And 213a. Evenflo argued that if “at NHTSA's option” refers to test options available to NHTSA as parte of its annual test compliance program, then the language is more appropriate for test procedures and not in the regulation. Attached with a lap and shoulder belt, with a tether attached. https://www.openlearning.com/u/curtishemmingsen-ss5t8n/blog/TheGreatestGuideToSafetyBeltWebbing