Question

what is the most common attribute of the <table> tag? a border b cols c height d width

Explanation:

In HTML, the <table> tag's most common attribute for basic table styling and structure definition is border, which is used to specify the border width of the table. The cols attribute is not a standard/common attribute for the <table> tag (it's more associated with <textarea> or deprecated in some contexts), and height/width are less commonly used as the primary or most common attribute compared to border for basic table setup (though they can be used for sizing, border is more fundamental for table appearance definition in basic usage).

Answer:

A. border