because of; owing to and due to

[MikeNewYork]

I believe the challenge of this problem is to ask you to select the BEST answer, which, obviously everybody agrees, is (d), rather than pick the correct answer.

Much of language choice is individual. When one has several options, all of which are idiomatic English and correct grammar, it is difficult to call one a "best" choice. :wink:

[Taka]

Thank you, Susie, Mike!

[Susie Smith]

Thank you, Susie, Mike!

You're welcome. :D

[MikeNewYork]

Thank you, Susie, Mike!

You're very welcome. 8)