Answer:
THIS is what you wrote, but it contains two errors -- that have NOTHING to do with your question. I will correct the errors and THEN answer your question.
YOUR sentence: In 1878 the world First Commercial Telephone Company was open by entrepreneurs in Connecticut.
Corrected sentence: In 1878, the world's First Commercial Telephone Company was opened by entrepreneurs in Connecticut.
Step-by-step explanation:
As written, the sentence has no active verb.
The active voice version would read:
In 1878, entrepreneurs in Connecticut opened the world's First Commercial Telephone Company.