What type of company does not provide backup support to Brigade Support Battalions (BSBs)?

The Support Maintenance Company is the correct answer because its primary role revolves around providing direct maintenance support to units in the field, rather than serving as a backup resource to the Brigade Support Battalions (BSBs). Its focus is specifically on repair and maintenance services for equipment, ensuring that units have operational capabilities while maintaining an independent operational tempo.

In contrast, the Combat Sustainment Support Battalion is designed to support the logistical needs of the brigade, often integrating closely with BSBs to ensure that supplies, transport, and maintenance services are well-coordinated. The Maintenance Surge Team is typically a temporary solution that can be activated to provide additional maintenance resources or support when demand exceeds regular capabilities, thereby functioning in a supportive role to the BSBs. Similarly, the Division Support Maintenance Company supports broader divisional needs and can assist BSBs in times of high operational tempo.

Thus, while the Support Maintenance Company has important responsibilities within the maintenance framework, it does not play the role of backup for Brigade Support Battalions, which are more integral in the logistics and support chain for the brigade as a whole.