Answer: Option 'E' is correct.
Step-by-step explanation:
Marginal utility is the addition utility derived from each successive unit of a particular good.
so, marginal utility is the change in utility from consuming an addition unit of a good or service.
Mathematically, it is expressed as

Hence, Option 'E' is correct.
The -2 has a multiplicity of 2
Since the order of (x+2) is squared, i.e. power is 2
I'm pretty sure it would be y=2x+9