The answer is $\boxed{\text{C}}$.
The sequence is $15, 16, 22, 29, 45, 70$. The difference between consecutive terms is $1, 6, 7, 16, 25$. The only term that does not follow this pattern is $45$. The difference between $45$ and $29$ is $16$, which is not a multiple of $7$. Therefore, $45$ is the wrong term.
Here is a table showing the sequence of numbers and the differences between consecutive terms:
| Term | Number | Difference |
|—|—|—|
| 1 | 15 | – |
| 2 | 16 | 1 |
| 3 | 22 | 6 |
| 4 | 29 | 7 |
| 5 | 45 | 16 |
| 6 | 70 | 25 |
As you can see, the difference between consecutive terms is $1, 6, 7, 16, 25$. This pattern continues until the fifth term, $45$. The difference between $45$ and $29$ is $16$, which is not a multiple of $7$. Therefore, $45$ is the wrong term.