Horizontal asymptote at
tells us that the original graph has been translated down.since
,
are positive. also we can say that the point
has a smaller
-coordinate than
.this means that the transformed exponential function is increasing as it goes to the right. as it goes from
to
, the value of the exponential function increases. it goes from
to something bigger,
. therefore, as
. the left hand would be the side that approaches the horizontal asymptote.so the answer is d