Math Q from the sets

[rajkoneru]

Is there a formula for this or is it that we just have to work out all the possible combinations.

Q33:
A photographer will arrange 6 people of 6 different heights for photograph by placing
them in two rows of three so that each person in the first row is standing in front of
someone in the second row. The heights of the people within each row must increase
from left to right, and each person in the second row must be taller than the person
standing in front of him or her. How many such arrangements of the 6 people are
possible?
A. 5
B. 6
C. 9
D. 24
E. 36

[StaceyKoprince]

I'm sorry we haven't responded to your question more promptly. Given the numerous constraints, the formula would be more complicated than just writing out the options.