Where is the correct position of the diaphragm?

Which one is the correct position of diaphragm in 1 to 4?
The answer is “2”.
The diaphragm is probably more upper located than you thought.
Oxygen flows only into the lungs, if the air were to flow into your belly, it would be fatal.
As I had stated before in previous pages, it is a misconception: People think that abdominal breathing means that air flows into the belly.
Correctly say, “if you move your stomach and back sufficiently, in such a way, it will put a substantial amount of air in your lungs.”
I would like you to know the facts and have a great voice.
If the exhalation just increases;
(1)The vocal chord vibration increases and the volume of voice gains..
(2)The efficiency of amplitude is improved and it is easier to hit high notes.
(3)The air current of exhalation is stable and Piano, Pianissimo both become more beautifully defined.
(4)You can vocalize without straining the throat because of Bernoulli theorem.
(5)Even if you are nervous, you can still sing stable without stopping.

It must be correct exhalation to achieve said results.
So, what is the correct exhalation exactly?
I: The movement of the abdominal cavity and chest are smooth.
II:The costal cartilages displays a stretch movement, and the costovertebral joints have a wide motion of range.
III:The part of larynx is not in the depth of place(It’s important for preventing LDP!)
IV:The epiglottis has mobility and stands vertically.
V:No rhinocleisis(e.g. nasal congestion or deviated septum)

There are still a lot of requirements though, the above is only a brief explanation for reference.
By the way, the correct exhalation for singing is not equal to breathing capacity. Although having a large breathing capacity can have advantages for breathing, the usage and strength of air flow is what decides how your voice is affected.
Note1:Please note that the above figure is a sketch and the position of diaphragm is rough.
Note2:The high register also relates strongly to the exhalation. The strong, clear and sustained high register is made by the process of exhalation, the resonance chamber and the cricothyroid muscle.The cricothyroid muscle produces tension and elongation of the vocal folds by drawing up the arch of the cricoid cartilage and tilting back the upper border of the thyroid cartilage lamina; the distance between the vocal processes and the angle of the thyroid is thus increased, and the folds are consequently elongated, resulting in higher pitch phonation.
Note3:If you lose the sound of a pitch halfway or toward the end of your stage, You are probably not exhaling correctly.