At "PrintMaster", a custom t$-$shirt printing store, the process for creating a personalized t$-$shirt involves the following sequential steps with one person in each step: $1)$ Customer design consultation $(20$ minutes$)$; $2)$ Design creation on the computer $(40$ minutes$)$; $3)$ Machine setup and calibration $(10$ minutes$)$; $4)$ Actual printing on the t$-$shirt and quality check $(20$ minutes$).$ What should PrintMaster do to increase production volume?

Implement advanced machines that require minimal setup and calibration time, streamlining the printing process.

Invest in faster design software or train the existing staff to speed up the design creation process on the computer.

Set up multiple printing stations to allow for simultaneous printing and quality checking of multiple t$-$shirts.

Hire additional staff for the customer design consultation to ensure that more customers can be catered to simultaneously.