Solution

The correct answer is both are equivalent Machines

Explanation:

First Machine (Top Diagram):

• States: A, B
• Alphabet: {a, b}
• Final State: B
• Transitions:
  From A:
  'a' -> stays at A
  From B:
  'a' -> moves to A
  'b' -> stays at B

​Second Machine (Bottom Diagram):

• States: A, B, C
• Alphabet: {a, b}
• Final State: B, C
• Transitions:
  From A:
  'a' -> moves to B
  From B:
  'a' -> stays at B
  'b' -> moves to C
  From C:
  'a' -> moves to B
  'b' -> stays at C

Bothe machines are NFA and both are accept same string.