From 800–1200, the khmer and mon peoples moved into the northern regions of
a. cambodia.
b. thailand.
c. vietnam.
d. myanmar

The question is the following: from 800–1200, the Khmer and Mon peoples moved into the northern regions of... To answer this, it is important to know that around 800 is when the Khmer empire was created - and the Khmer empire was the state out which modern Cambodia is the succesor of. The answer is a) Cambodia

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion