What is the value of the first quartile, (q1)?
a .5
b 3.5
c 2.25
d 1.5

We have
0.5, 1.5, 2.25, 3.0, 3.5
then the median is 2.25, we have the two halves:
h1 = 0.5, 1.5
h2 = 3.0, 3.5
so the first quartile, Q1 is the median of the lower half of the data:
Q1 = (0.5 + 1.5)/2
Q1 = 1