Answer:
the 1st answer option
Explanation:
an irrational number has an infinite number of digits after the decimal point with any repeating pattern.
-4.8237 has only a finite number of digits after the decimal point. not irrational.
4 + sqrt(25) = 4 + 5 = 9 that is a very rational number (so, not irrational).
pi (and therefore also pi/2) is per definition irrational.
the cubic root of 4 has no "clean" finite solution as sqrt(4). so, this is also irrational.