AI solution for React Quiz on BFE.dev
4. React re-render 4

The code outputs the following by console.log:

App
A
B
C
A
D

This is because when App component is rendered, it logs 'App' to the console. It contains two components A and D, which are subsequently rendered. First, A is rendered with B as its child. This logs 'A' to the console and then useState is called, updating the state with a value of 1. This triggers a re-render of A, logging another 'A' to the console. Then, B is rendered as a child of A, logging 'B' to the console. Finally, C is rendered as a child of B, logging 'C' to the console. After this, D is rendered, logging 'D' to the console.