The distance measured by a degree of longitude
decreases as you move from the equator toward the poles
is constant
increases as you move from the equator toward the poles
is always about 111 km

I'm pretty sure it's c. extremely gradual but not 100% sure though.

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

I’m guessing probably a

Most of the land is used for housing/commercial uses