Solution: ∫ point A(m, n) is on the straight line x+2y= 1, where Mn > 0,

∴m+2n= 1,m,n>0.

Then 2m+1n = (m+2n) (2m+1n) = 4+4 nm+Mn ≥ 4+24 nm? Mn = 8。 Take the equal sign if and only if m=2n= 12.

The minimum value of ∴2m+ 1n is 8.

Therefore, choose: B.