Final answer:
Quebec has an explicit ban on unsolicited cold calls by registered sales representatives to non-clients for selling securities. This regulation aims to protect investors and ensure ethical practices in Quebec's securities industry.
Step-by-step explanation:
The province in Canada where there is an explicit and absolute ban on making "unsolicited" or "cold calls" to non-clients in an effort to sell securities is Quebec. According to the province's securities legislation, registered sales representatives are prohibited from making unsolicited telephone calls or personal visits to non-clients to solicit mutual fund trades.
This measure is part of a broader strategy to protect investors and maintain fair and ethical business practices in the securities industry in Quebec.