In my experience, both take a great deal of courage.

I'd say both take courage.

Giving you true opinion
It shows people who you are

Huh? I'm agin it, dagnabit.

I think a little of both for me

Giving your true opinion. Especially here.

Questions definitely. Especially when the subject something other consider to be unquestionable.

Neither. People love giving opinions and talking about themselves.

neither are fearless activities.

Neither. Making a statement takes the most courage

sticking your head in a hungry lion's mouth

Sharing an opinion. Even about oneself. Tell the world you're highly sensitive and emotional, and some stranger will react that you're in fact autistic.

Expressing an opinion will lead nowhere, because people tend to see opinions as irrelevant and insignificant anyway ("it's only her opinion"), whereas asking questions may irritate people.

depends on what the question or opinion might be

I dont think courage is the right word here.

I think if a person is afraid to speak freely they have had an experience that hindered their self confidence at some point in thier life.

I teach a class that sometimes deals with controversial topics. I rarely have a bad reaction to a question, but there are some opinions I refuse to share because I know the response will be negative and lead to a discussion I want to avoid.

Probably asking a question.

That's often enough to attract derision and antagonise a responder.