Draw lines through corners.
None of your examples seem correct to me. While almost everyone uses area templates, the rules specify that you have to draw lines out from the chosen center point until you hit an obstruction or reach the limit of the effect’s radius. These are known as lines of effect, and are actual, geometrical, 1-dimensional lines, not Line-shaped areas.
A burst, cone, cylinder, or emanation spell affects only an area, creatures, or objects to which it has line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, a cylinder’s circle, or an emanation’s point of origin).
A square is within the area if you can draw such a line of effect from the origin to any point in the square (and the distance to the square is not greater than the effect’s radius, of course).
However, if the square has at least one corner that you cannot draw a line of effect to, the target has Cover and receives a +2 bonus on Reflex saves against the burst.
Cover grants you a +2 bonus on Reflex saves against attacks that originate or burst out from a point on the other side of the cover from you. Note that spread effects can extend around corners and thus negate this cover bonus.
To determine whether your target has cover from your ranged attack, choose a corner of your square. If any line from this corner to any corner of the target’s square passes through a square or border that blocks line of effect or provides cover, or through a square occupied by a creature, the target has cover (+4 to AC).
Note that these rules have a bit of a discrepancy, since the definition of cover refers to the concept as being specifically for the sake of ranged attacks, which a burst wouldn’t be. I don’t consider this a particularly meaningful discrepancy but it should be mentioned.
Since the effect is centered on the top wall, a line through the top corner of the doorway extends straight to the right. Thus, everything above the doorway is not included in the area. This nixes the second and third drawings.
A line drawn through the bottom doorway, on the other hand, continues out into the room at an angle, rather than straight. This nixes your first drawing. The bottom half of the second drawing is close to correct, but includes two squares that are outside the range of the effect: the bottom-right-most square and the one directly above that one.
Note the above does not include the two squares that are affected but where creatures would benefit from Cover. The circular radius-limit is also misleading