Answer: a. topical
Step-by-step explanation:
The topical pattern of speech is the pattern which is commonly used. It typically work when other pattern of speech do not work. A topical pattern arranges the information according to sub-topics within a main topic. In other words the small topics fall under large topics. Using this pattern each type represents the main section of information in sub parts.
The given pattern of speech is an example of topical type of organization of speech because the topic has many parts.