Question about Grounding in this Circuit

[rtareen]

TL;DR

I want to know why the voltage at point b is zero even through it comes before the grounding point in the circuit.

Click the attached file to see the figure and the book's explanation. The explanation for 27-7 (a) makes sense as the point a comes after the grounding point and before anything else. Therefore it should have a potential of zero. But, to me, 27-7 (b) doesn't make any sense. Why should the potential $V_b$ be zero when it comes before the grounding point? Shouldnt any point after the grounding symbol, but before the resistor, have a potential of zero? Why is the voltage at b zero?

 

[Kyouran]

It doesn't matter whether it comes before or after, the voltage for the entire top portion between the internal resistor of the battery and the resistor to the right is all the same, it is all zero.

 

[rtareen]

It doesn't matter whether it comes before or after, the voltage for the entire top portion between the internal resistor of the battery and the resistor to the right is all the same, it is all zero.

Oh ok Thank you