Which of the following is NOT among the three types of authentication mechanisms?

For each numbering base system, the far right always has a place value of ________

Fill in the blank(s) with correct word

Which of these was not a primary characteristic of computer use in the 1950s and 1960s?

A. Located at a central site B. Served as an Internet host computer C. Programmed and operated by computer professionals D. Used to automate transaction processing and prepare management reports