Final answer:
D) 1970s
The first modern cell salvage machines were introduced in the 1970s, marking an important development in medical technology for intraoperative blood recovery.
Step-by-step explanation:
The first modern cell salvage machines, which are essential in medical procedures for recapturing and reusing patients' blood, were made available in the 1970s. These machines are an important part of intraoperative blood recovery, contributing to blood conservation and reducing the need for blood transfusions from donors. Cell salvage technology represents a significant advancement in medical engineering, allowing for safer and more efficient surgical procedures.