When dialing a land-line phone in Japan from outside the country normally the pattern is to dial the country code (+81) and then remove the first zero from the area code. For example, to call Osaka from the US you would dial this:

011-81-6-xxxx-xxxx

The area code for Osaka is 06. Tokyo is 03. When calling from overseas you would strip the first zero.

My question is whether this same pattern applies to calling mobile phones or IP phones that don’t have area codes, but use the prefix 0×0:

Ex.
090, cheap prescription drugs 080, 070, 050

If my mobile phone number in Japan was 090-xxx-xxxx which pattern would be correct when explaining how to call from outside Japan:

A. (Country Code) +81 090-xxxx-xxxx
B. (Country Code) +81 90-xxxx-xxxx

For international calls do you strip the first zero with mobile phones in Japan or not?