Consider the following DFA that generates set of strings over Σ = {a, b, c}…

Key idea: the automaton has two mirrored sets of three states that track progress through the substring "abc" and flip parity each time a complete "abc" is seen.

• Even-parity states (start and accepting): a 3-state chain that represents having seen an even number of complete "abc" occurrences so far.

• Odd-parity states: a mirrored 3-state chain that represents having seen an odd number of complete "abc" occurrences so far.

How the transitions implement this:

1. From the even group: the start state (call it even-0) goes to even-1 on 'a' and loops on 'b' and 'c'. even-1 (after seeing 'a') goes to even-2 on 'b' (and stays on 'a'); even-2 (after seeing 'ab') goes to the odd group on 'c' (completing "abc" and toggling parity), while other letters send it to the appropriate partial-match states.

2. The odd group mirrors these transitions: reading 'c' after the odd group's 'ab' state completes another "abc" and returns to the even group's start state, toggling parity back to even.

Accepting condition and conclusion:

• Because the accepting states are exactly those in the even-parity group, the DFA accepts precisely those strings that contain an even number (including zero) of occurrences of the substring "abc".

• Therefore the correct description of the language is the set of strings whose count of the substring "abc" is even (0,2,4,...).