Beginning in the $1980\text{'}$s$,$ manufacturers utilized $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ and total quality management $($TQM$)$ strategies to improve quality, manufacturing efficiencies, and delivery times. $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.$

a$.$ Co$-$sourcing

b$.$ Customer participation approach

c$.$ Segmenting customers by profitability

d$.$ Just$-$in$-$time $($JIT$)$