Final answer:
Thomas Hopkins Gallaudet believed that freedom of communication, pivotal for education, is achieved through sign language, and he was instrumental in using it to teach the deaf.
Step-by-step explanation:
The individual who believed that freedom of communication is key to education and that this freedom is achieved through sign language is A) Thomas Hopkins Gallaudet. Gallaudet is recognized for his pioneering work in the education of the deaf and was the founder of the first school for the deaf in North America, which opened in Hartford, Connecticut, in 1817. This school, now known as the American School for the Deaf, utilized sign language as a medium for imparting education to students with hearing impairments, championing the idea that effective education can be achieved through non-verbal means of communication.