The IUPAC name of compound shown below is

The compound is a six-membered ring containing one double bond, which makes it a cyclohexene.

The carbons of the double bond must be numbered C1 and C2. The numbering should proceed around the ring in a direction that gives the substituents the lowest possible locant numbers. If there's a tie, alphabetical order of substituents determines which carbon gets the lower number.

Let's consider the two possible ways to number the double bond carbons as C1 and C2:

• Option 1: Let the carbon bearing the chlorine atom be C1. The double bond is between C1 and C2. Numbering clockwise from C1:

  • C1: has Cl
  • C2: part of double bond
  • C3: has Br
  • C4, C5, C6 In this case, the substituents are at positions 1 (chloro) and 3 (bromo). The double bond is between C1 and C2, so it's cyclohex-1-ene. The locant set for substituents is (1, 3).

• Option 2: Let the carbon not bearing the chlorine atom (but still part of the double bond) be C1. The double bond is between C1 and C2. Numbering clockwise from C1:

  • C1: part of double bond
  • C2: has Cl
  • C3: has Br
  • C4, C5, C6 In this case, the substituents are at positions 2 (chloro) and 3 (bromo). The double bond is between C1 and C2, so it's cyclohex-1-ene. The locant set for substituents is (2, 3).

Comparing (1, 3) from Option 1 and (2, 3) from Option 2, the set (1, 3) is lower at the first point of difference (1 < 2). Therefore, Option 1 is the correct numbering. The chlorine is at C1, and the bromine is at C3.

The substituents are bromo (at position 3) and chloro (at position 1). According to alphabetical order, "bromo" comes before "chloro". The parent ring is cyclohexene. The position of the double bond (1-ene) is often omitted for cyclohexene as it's implied to be between C1 and C2.

Thus, the IUPAC name is 3-bromo-1-chlorocyclohexene.

Comparing this with the given options:
(A) 2-bromo-6- chlorocyclohex-1-ene
(B) 6-bromo-2-chlorocyclohexene
(C) 3-bromo-1-chlorocyclohexene
(D) 1-bromo-3-chlorocyclohexene

The correct option is (C).

The final answer is $\boxed{\text{C}}$