Three distinct antigens $X, Y$ and $Z$ were used to raise antibodies. Antigen $Z$ was injected in a mouse on day zero followed by the administration of antigens $X$ and $Y$ on day $28$. A second injection of antigen $X$ was administered on day $70$. The antibody titers were monitored in the serum every day and the results are shown below:

Which one of the following statements regarding the antibody titers in the serum is INCORRECT?

1. $Z$-specic IgG Will be high on day $14$
2. $X$-specic antibody titer will be high on day $84$
3. $X$-specific IgG will be high on day $42$
4. $Y$-specific IgG will be high on day $84$