Contrasts live inside a factor not across two

Consider the two-way ANOVA model $Y_{ij}=\mu +{\alpha }_i+{\beta }_j+{\epsilon }_{ij},i=1,2;j=1,2$, where $\mu$ is the overall mean effect, ${\alpha }_i$ is the effect of the i-th level of factor $A,{\beta }_j$ is the effect of j-th level of factor $B,Y_{ij}$ is the response of the (i, j)-th experimental unit and ${\epsilon }_{ij}$ is the corresponding error with $E({\epsilon }_{ij})=0$ for i = 1, 2; j = 1, 2. Which of the following are estimable linear parametric functions?