From 2012 to 2015, how many complaints were submitted via email from female clients?
from 2012 to 2015 refers to Date received BETWEEN 2012 AND 2015; submitted via email refers to Submitted via = 'Email'; female refers to sex = 'Female'
SELECT COUNT(T1.client_id) FROM client AS T1 INNER JOIN events AS T2 ON T1.client_id = T2.Client_ID WHERE strftime('%Y', T2.`Date received`) BETWEEN '2012' AND '2015' AND T2.`Submitted via` = 'Email' AND T1.sex = 'Male'