a) The man, who I never knew his name, drove me home.

b) The man, on whom I never knew the name, drove me home.

c) The man, who I never knew the name of, drove me home.

1) b and c seem OK, but what is wrong with a?

2) Is this OK below?

I, who am happy, strolled down the street, laughing.

My 2 cents...
The man, whose name I never knew, drove me home,
Yea, yours is right, but just don't know why mine is incorrect.