Final answer:
Option (a) ∠1 < ∠3 is incorrect as ∠1 is not smaller than ∠3.
Step-by-step explanation:
The incorrect option is option (a) ∠1 < ∠3.
When we compare angles, we use the symbol (<) to represent 'less than.' So, if angle ∠1 is smaller than angle ∠3, we write it as ∠1 < ∠3.
Therefore, the correct statement would be ∠1 > ∠3, making option (a) incorrect.