In value chain analysis, $($a$)$ is a primary activity and $($b$)$ is a supporting activity.

$($a$)$ Recruiting $-($b$)$ Outbound logistics

$($a$)$ Inbound Logistics $-($b$)$ Procurement

$($a$)$ Research & Development $-($b$)$Operations

$($a$)$ Technology Development$-($b$)$ Marketing and sales