Can someone help me with the value of d?

a 84

b 80

c 100

d 50

hey,see the attachment

Explanation:

i got answer which is not matching with the options

Once you check your question

these nuts

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.