Dental hygiene, Diagnostic medical sonography (ultrasound), or Respiratory Thera!

Dental hygiene, Diagnostic medical sonography (ultrasound), or Respiratory Therapy?

Which job make more money and which do you prefer and why? (I research on the salary of each major and to me it seem like the other two major make more money, but some people who answer my question say that Dental hygiene make more money, is that true?)
Also, does Dental hygiene need to pass the state exam in order to work? if I live in San Jose, how much money can I make with an A.S. degree in Dental hygiene? Plus, do I need a bachlor degree to in a company or for the government?

Hey. I was looking into this a couple months ago, and from what I found Dental Hygiene gives the most pay. Thats what Im really looking into being. In order to get certified you need at least an associate degree. Some of the other jobs listen can take more than that and still make less money :( I live in the midwest and dental hygiene rates here are like 40,000 dollars a year and thats just part time! Im sure in Cali it would be 60,000 or more. And yes, they do have to pass the state exam as well, but other than that in order to just be a basic dental hygienist, from what I've looked up all you need is an associate degree and a certificate and liscence from whatever state you live in. Seriously, i think its a great job that makes great pay for what you do! I would totally look into it more! Hope I helped! Good luck! :)