The length and depth of the generalized table (a, (a, b), D, e, ((I, J), K)) are (). A.5,3 b.5,5 c.6,4 d.6,6 respectively

The length and depth of the generalized table (a, (a, b), D, e, ((I, J), K)) are (). A.5,3 b.5,5 c.6,4 d.6,6 respectively

Length is 5, depth is 3, choose a

Is the depth of generalized table the number of brackets (positive brackets + negative brackets) / 2? What is the length and depth of ((x, (a, b)), ((x, (a, b)), y))?
I'm counting six brackets. Why isn't the depth 6 but 4?

Depth is the largest level of nested parentheses, so look at it this way:
( (x,(a,b) ),( (x,(a,b) ),y) )
1 2 3 21 2 3 4 3 2 1 0
As for the length, it is the number of elements in the first layer, so it is 2
The first element is the sub table (x, (a, b)), and the second element is the sub table ((x, (a, b)), y)

Which international river is known as "Asian Danube"

Mekong River is the most important international river in Southeast Asia