Write a regular expression to match below strings and return the string with substituted value as "startdate" in python.
start_date
date_start
dates start
date
start_da

William travels a lot on business purpose. he needs to regularly communicate with his business partner. he also needs to send out weekly reports to his boss while he is traveling. which web-based application best suits william’s needs? (social media, webmail, wiki) is the best web-based application for william. he can access this application via the internet using a (digital cable, fax machine, web browser).