Which of the following is NOT a data visualization option available in Smartsheet?

C. Flowcharts is the correct answer because, while Smartsheet provides various options for data visualization to help users interpret and present their data clearly, flowcharts are not one of those options. Smartsheet offers tools that allow users to create bar charts, pie charts, and Gantt charts, which are vital for project tracking and reporting.

Bar and pie charts help summarize and display quantitative data, allowing users to identify trends and make decisions based on visual representations. Gantt charts are particularly popular in project management for outlining project timelines and dependencies. Flowcharts, on the other hand, typically serve to map out processes or decision trees and are not directly supported as a visualization type within Smartsheet. Thus, the absence of flowcharts among the visualization options provided by Smartsheet makes it the right choice for this question.