What is the relationship between a base and the number of symbols in a positional number system​?

the value of a symbol is given by the weight of it's position expressed in the bases of the system (or radices)

solution:

the right option is a

to adding   a new row to a table we   have to do process last table cell and pressing tab.

this is the process to add new row in the cell:

* to add a row below the cell, click insert below in the rows and columns group.

thus this is the required right answer.