Question regarding the construction of Datum system

[[An...]]

Hi, i'm trying to create the Datum system of this drawing:

but using just the point in this way result in an error:

I thought of making geometric element from points but have trouble with B and C :

A is easy, Plane from 3 points;

B could be also plane from 3 point but i don't thinks that right since it seems that the datum b is perpendicular to the plane for point B1,2,3

C i was thinking of making 2 lines, C1-C3 and C2-C4 and intersecate the to create point C.

Any suggestion for Datum B? Thoughts of Datum C?

Thanks in advances 

Best regards

Andrea

[[Ma...]]

How does your callout looks like?

A1-3 - ok - it's a plane
B1-3 - not ok - it's not a plane - perhaps B1-2 as direction / B3-B1/2 as origin in let'S say X
C1-4 - not ok - it's not a plane - perhaps origin in XY or just Y ( X taken by datum B )

It would be better to ask engineer if there are question - without callout i can not tell more.