Which of these is an inappropriate shift in verb tense?

Cody is laughing at Megan's joke when suddenly the phone went dead,

He tries calling her back, but she is not answering,

A. Cody is laughing

B. She is not

C. He tries calling

D. Phone went dead

"A: Cody is laughing " is an inappropriate shift in the verb tense in the given sentence "Cody is laughing at Megan's joke when suddenly the phone went dead, He tries calling her back, but she is not answering."

Explanation:

The reference of the sentence is that Cody was laughing at Meghan's joke, i. e. something happened in the past and the phone went dead. Now, when he is trying to call her back, she is not answering. The second part of the sentence when Cody is trying to call her again and she not answering is in present tense, so options B and C are in correct verb tense. Option D is also correct, because action happened in the past, so 'went' is used in "phone went dead".

Incorrect verb tense is "Cody is laughing" as this action happened in the past and it should be "Cody was laughing".