The outline form for a Class I amalgam preparation is determined by all of the following EXCEPT the

need to terminate the margins on a cusp ridge or marginal ridge crest.

extent of undermining of the enamel by the carious process.

extension that must be made along the fissures in order to achieve sound and smooth margins.

lateral spread of caries along the dentino-enamel junction.

extent to which the enamel has been involved by the carious process.