Statistical Inference — size of a randomized test

Let $x_1,x_2,x_3,x_4$ be a random sample from Poisson distribution with mean $\lambda>0$. To test $H_0:\lambda=1$ versus $H_1:\lambda=1.5$, the following randomized test is considered: $\varphi(x)=1$ if $\sum_{i=1}^4 x_i>2$, $0.1$ if $\sum_{i=1}^4 x_i=2$, $0$ if $\sum_{i=1}^4 x_i<2$. (Given $e^{-4}\approx0.0183$ and $e^{-6}\approx0.0025$.) The size of the randomized test is within the interval: