Meaning of 'Merely playing for time'

Test No. [color=blue]incompl/advan-14 “Time Expressions (2)”, question 3

My opinion is that they don’t know what to do and are merely playing time.

(a) to
(b) for
(c) at
(d) in

Test No. [color=blue]incompl/advan-14 “Time Expressions (2)”, answer 3

My opinion is that they don’t know what to do and are merely playing for time.

Correct answer: (b) for

Hi Alan and Torsten! Explain me, please! …Merely playing for time

Thank you

Ariadna

Hi,

Just waiting to get extra time.

Alan

Hello Alan! Thank you!
Ariadna

How else do you say this? Gaining time? Is it correct?

Expressions with “for time

-be hard pressed for time = be pushed for time
-be pressed for time
-i am pushed for time
-play for time =stall for time

for a time = stay somewhere for a time
…= I lived in Egypt for a time.

for some time= for a fairly long period

I worked in this school for some time.