How many double bond equivalents (degree of unsaturation) does amoxycillin possess?

How many degrees of unsaturation are there in the following compound?

Match List-$I$ with List-$II$.
| List-$I$ | List-$II$ |
| :--- | :--- |
| $(A)$ Tetrahydrofuran | $(I)$ Spiro compound |
| $(B)$ Bicyclo[$1.1$.$0$]butane derivative | $(II)$ Aromatic compound |
| $(C)$ Spiro[$2.2$]pentane derivative | $(III)$ Non-planar heterocyclic compound |
| $(D)$ Furan | $(IV)$ Bicyclo compound |
Choose the correct answer from the options given below.

The least acidic compound among the following is:

Homologues have different

Two unknown compounds $X$ and $Y$,both having molecular formula $C_4H_8O$,give the following results with four chemical tests.

Compound	Bromine	$Na$ metal	Chromic acid	Lucas reagent
$X$	decolourises	bubbles	Orange to Green	No reaction
$Y$	No reaction	No reaction	No reaction	No reaction

Compound $X$ and $Y$ respectively are: