The correct option is 'b) soon'.
Translation:
Джейн и Роуз скоро вернутся домой.
Explanation:
'Soon' fits the context best, indicating that Jane and Rose will return home in the near future. 'After' and 'before' require additional context to be meaningful, such as 'after school' or 'before dinner'. Without that context, 'soon' is the most logical choice.