Question

Multiple Choice ( Select 1 out of 4 options, for the question below.)
Rule of union is
Options
If a Ⓡ b holds and a ®g holds, then a Ⓡbg holds
If a ® bg holds, then a Ⓡb holds and a Ⓡg holds
If a Ⓡb holds and g b ®d holds, then a g® d holds
All of the above​

Answer 1

Answer:

all of above.................