The verbal in this sentence is participle
Explanation:
A participle is a form of verb which is used to describe something else and it do not take the noun these types of verbs are called participles. They end with –ing. A gerund is a type of verb which is used to take the verb completely into noun form and this also ends with –ing.
Infinitives are employed with to=base verbs and they are called as infinitives. In the given sentence not realizing describes the old women and hence it is a participle.
