How many steps of glycolysis are irreversible?

A)

3steps→1st,3rdandlast

B)

3steps→1st,5thandlast

C)

2steps→1st,last

D)

1st step only

Glycolysis is a metabolic pathway that converts glucose into pyruvate. The free energy released in this process is used as ATP and NADP.
There are ten steps in the glycolysis pathway out of which 7 are reversible and 3 are irreversible.
The irreversible steps are a conversation of glucose into glucose 6 phosphate, fructose into 1,6 biphosphate and phosphoenolpyruvate into pyruvic acid.

So, the correct option is '3 steps -- 1st, 3rd and last'.