I say the answers is A but if you mean ventilation in the area of the room then answer B
Hopefully that helps you out and is this for history or science?
I would love to answer but unfortunately there is no picture.
Answer
given,
a = 2 t - 10
velocity function
we know,


integrating both side

v = t² - 10 t + C
at t = 0 v = 3
so, 3 = 0 - 0 + C
C = 3
Velocity function is equal to v = t² - 10 t + 3
Again we know,


integrating both side


now, at t= 0 s = -4

C = -4
So,

Position function is equal to 
Answer:
a, c
Explanation:
As the problem statement tells you, the phasor technique cannot be used when the frequencies are different. The frequencies are different when the coefficients of t are different. The different ones are highlighted.
a. 45 sin(2500t – 50°) + 20 cos(1500t +20°)
b. 25 cos(50t + 160°) + 15 cos(50t +70°)
c. 100 cos(500t +40°) + 50 sin(500t – 120°) – 120 cos(500t + 60°) -100 sin(10,000t +90°) + 40 sin(10, 100t – 80°) + 80 cos(10,000t)
d. 75 cos(8t+40°) + 75 sin(8t+10°) – 75 cos(8t + 160°)