Which of the following correctly use conjunctions and punctuation? Check all that apply.
China's one-child policy has had an impact on families, it was instituted in 1970 to control population growth.
Since it was instituted in 1970 to control population growth, China's one-child policy has had an impact on families.
China's one-child policy has had an impact on families since it was instituted in 1970 to control population growth.
O China's one-child policy has had an impact on families, when it was instituted in 1970 to control population growth.