The Number of Typographical Errors in a Document Follows a Poisson

Multiple Choice

The number of typographical errors in a document follows a Poisson distribution with a mean of 2 errors per page. Let $X$ represent the number of errors on 4 pages. Find $\sigma _ { x ^ { * } }$

A) 8
B) 3.8
C) 2.8
D) 2