What is purchasing$$s input to the sales and operations planning $($S&OP$)$ process?

Purchasing coaches operations on manufacturing best practices

Purchasing provides crucial information on pricing, supplier capabilities, and quality

Purchasing conducts training of the sales force in how to deal with buyers

Purchasing runs the S&OP process and has the final say in decision$-$making

Purchasing has no inputs to this process $$ only sales and operations are involved