At Line 1, LHS>>>> b[0][1] primitive type... RHS>>>> b3 byte primitive type. One byte can be assigned to another byte type. CORRECT.
At Line 2, LHS>>>> b2[1][2][0] is 1-D Array... RHS>>>> b3 byte primitive type. One byte can't be assigned to 1-D byte array. WRONG
At Line 3, LHS>>>> b2[1][2][1][0] is primitive type... RHS>>>> b3 byte primitive type. One byte can be assigned to another byte type. CORRECT.
At Line 4, LHS>>>> b2[1][2] is 2-D byte array... RHS>>>> b is also 2-D byte array. Again can be assigned. CORRECT.
PLZ view a similar post here...
https://coderanch.com/t/255494/java-programmer-SCJP/certification/scjp-qtn-Mult-dimensional-array regards
NaK