If I'm in a foreign country, and a caller in the U.S. calls my T-Mobile phone, am I charged extra if I answer the call in the foreign country and talk on my T-Mobile phone?

If I'm in a foreign country, and a caller in the U.S. calls my T-Mobile phone, am I charged extra if I answer the call in the foreign country and talk on my T-Mobile phone?

If I'm in a foreign country, and I call a number in the U.S., am I charged extra for originating and talking on that call?

If I'm in a foreign country with a friend who has a U.S. number on his cell phone, and I call him while we're both in the foreign country, am I charged extra for originating and talking on that call?

I have a SMB Unlimited Talk and Text plan.

Thank you.