Which one is the most suitable translation for the following?
原文： 这项新举措无疑给工人们吃了一颗定心丸。
A、This new measure has undoubtedly made the workers feel relieved. 
B、Undoubtedly, this new measure is a panacea for the workers.
C、This new neasure has undoubtedly given the workers a relieving pill.
D、Undoubtedly, this new measure has set the hearts of the workers back in place.