The IUPAC name of the compound

is

The given structure, represents a three-carbon chain (propane) in which an O atom bridges the first and second carbon atoms, forming a three-membered cyclic ether (an epoxide).

Step 1 - Select the parent chain.
The longest continuous carbon chain contains three carbon atoms, so the parent hydrocarbon is propane.

Step 2 - Identify and locate the functional group.
An oxygen atom is bonded to C-1 and C-2, creating an $$\ce{C-O-C}$$ bridge. According to IUPAC, such a bridge on adjacent carbons is named as an “epoxy” substituent. Its locants are written as “1,2-epoxy”.

Step 3 - Number the parent chain.
Number the propane skeleton from the end that gives the lowest possible set of locants to the epoxy group. Either direction gives 1 and 2, so we keep the conventional left-to-right order.

Step 4 - Assemble the name.
Prefix (position, type of bridge): $$1,2\text{-epoxy}$$
Parent name: propane

Complete IUPAC name: 1,2-Epoxypropane.

Therefore, the correct option is:
Option D which is: 1, 2-Epoxy propane