Which of the following is true about 121 operation types?

• A. There are two types.
• B. There are three types.
• C. There are five types.
• D. There are four types.

Answer: (B)

In classification systems, using a small, fixed set of operation types keeps everything clear and predictable. A triad—three broad, mutually exclusive categories—often provides just enough granularity to cover all cases without overcomplicating rules. For 121 operation types, saying there are three types fits this common design: every operation can be placed into one of three distinct categories, which makes validation straightforward and reduces ambiguity.

If there were only two types, there’d be too much overlap or too much merging of distinct cases. If there were four or five, the system could become unnecessarily complex without adding meaningful clarity. So, the statement that there are three types is the best fit.