English grammar

[MMiller]

Hi guys! please help me!
I am studying English grammar and having some troubles with this question:
I hope you to express an opinion about:
When I called them, they didn't answer. They pretended........already:
a. to sleep
b. sleeping
c. having slept
d. to have been sleeping
According to me, both answer A and answer D can be correct but I have never seen structure: to have been sleeping.
So, which one is correct?, Please help me.
Thanks so muchbest cordless drill best miter saw best gaming laptop under 500 best reel mower

[jonathanrace]

D.

This is an example of using the present perfect progressive tense.

An action that was continually happening in the past and is still continually happening.

[JamesWatson]

The answer D is correct.

[MMiller]

D.

This is an example of using the present perfect progressive tense.

An action that was continually happening in the past and is still continually happening.

Thanks Sir for answering with explanation

[jonathanrace]

You're quite welcome, good luck!