Under Clause (3) of Section 38 of the Specific Relief Act, 1963, perpetual injunction can be granted when

First, what is a perpetual injunction? It's a court order that permanently stops someone from doing something.

Now, let's look at the options:

Option A: The defendant is not a trustee of property for the plaintiff. This isn't directly related to when a perpetual injunction is usually granted. Trust relationships are usually covered in other clauses.

Option B: There exists a standard for ascertaining the actual damage caused. If we *can* easily figure out the exact financial damage, courts often prefer to award compensation (money) instead of a permanent ban (injunction). So, this would *not* be a good reason for a perpetual injunction.

Option C: Compensation would afford an adequate remedy. This is similar to Option B. If money can fix the problem, the court likely won't issue a perpetual injunction.

Option D: It is necessary to prevent multiplicity of proceedings. This means that without the injunction, there will be a lot of cases for the same subject matter in court one after the other. This *is* a valid reason for a perpetual injunction because it saves time and resources for everyone. The court doesn't want to deal with same problem again and again.

Therefore, the correct answer is Option D: It is necessary to prevent multiplicity of proceedings.