Step 1: Read the two statements.
Statement I says the ossification test (a bone fusion test) is the final test to decide a juvenile's age. Statement II says statutory documents like a birth certificate get precedence in deciding age. We must judge which are true.
Step 2: Understand age determination.
When deciding if a person is a juvenile, the law follows a clear order of preference. It trusts reliable documents first and turns to medical tests only when documents are missing.
Step 3: Test Statement I.
The ossification test is only a supporting medical estimate, and it gives an age range, not an exact final answer. It is used when documents are not available. So calling it the final test is wrong. Statement I is false.
Step 4: Test Statement II.
Under the Juvenile Justice (Care and Protection of Children) Act, a birth certificate from the school or municipal authority is given precedence over medical tests like ossification. So Statement II is true.
Step 5: Combine the findings.
Statement I is false and Statement II is true. So only Statement II is true.
Step 6: Eliminate the wrong options.
Both false is wrong because II is true. Both true is wrong because I is false. Only Statement I is true is wrong because I is the false one. So the only fitting choice is that only Statement II is true.
Step 7: Final answer.
\[ \boxed{\text{Only Statement II is true}} \]