The image depicts a state machine with the following states:
* S1
* S11
* S2
* S21
The state machine transitions are labeled as follows:
* gxSH - This triggers the transition from the initial state to S1.
* E - This event triggers the transition from S11 to S21.
* exS1 - This signifies exiting state S1.
* exS11 - This signifies exiting state S11.
* entS2 - This signifies entering state S2.
* entS21 - This signifies entering state S21.
* actnE - This indicates an action associated with the E event.
Given the state machine is currently in state S11 and an event of type E occurs, here's the sequence of behavior executions:
* actnE: The action associated with event E is executed.
* exS11: The state machine exits state S11.
* exS1: Since S11 is nested within S1, exiting S11 also implicitly triggers exiting S1.
* entS2: The state machine enters state S2.
* entS21: The state machine enters the nested state S21.
Justification for excluding other options:
* Option A (actnE; exS1; exS11: entS21; entS2) has the order of entering S2 and S21 reversed.
* Option C (exS11; actnE; entS2) omits the execution of the action associated with event E.
* Option D (gxSH; exS1; actnE; entS2) includes the irrelevant initial transition trigger (gxSH).
* Option E (exS11; exS1; actnE; entS2; entS21) has an extra exiting of state S1, which is not part of the valid transition path.
Following the state transitions and action triggers depicted in the state machine diagram, option B accurately reflects the sequence of behaviors that occur when event E triggers a transition from state S11.