The acidic, basic and amphoteric oxides, respectively, are:

First, we recall the general rule about the nature of oxides. Oxides of highly electropositive metals (especially the alkali and alkaline-earth metals) are basic. Oxides of non-metals are usually acidic because the non-metal is electronegative and pulls electron density away from oxygen, making the O atom less able to donate a pair. Finally, certain metal oxides lying near the metal-non-metal border (for example $$Al,\,Zn,\,Sn,\,Pb$$) can behave both as acids and as bases; these are called amphoteric oxides.

We now analyse every oxide that appears in the four options one by one, classifying each as acidic, basic or amphoteric.

1. $$Na_2O$$
Sodium is an alkali metal. Alkali-metal oxides react with water to give a strong base: $$Na_2O + H_2O \rightarrow 2\,NaOH$$. Hence $$Na_2O$$ is basic.

2. $$SO_3$$
Sulphur is a non-metal, and its oxide reacts with water to give sulphuric acid: $$SO_3 + H_2O \rightarrow H_2SO_4$$. Therefore $$SO_3$$ is acidic.

3. $$Al_2O_3$$
Aluminium lies on the diagonal boundary between metals and non-metals. Its oxide dissolves in acids as well as in strong bases, showing dual behaviour:

$$Al_2O_3 + 6\,HCl \rightarrow 2\,AlCl_3 + 3\,H_2O$$ (acts as a base)

$$Al_2O_3 + 2\,NaOH + 3\,H_2O \rightarrow 2\,Na[Al(OH)_4]$$ (acts as an acid)

Hence $$Al_2O_3$$ is amphoteric.

4. $$Cl_2O$$
Chlorine is a non-metal; its oxide reacts with water to form hypochlorous acid: $$Cl_2O + H_2O \rightarrow 2\,HOCl$$. Thus $$Cl_2O$$ is acidic.

5. $$CaO$$
Calcium is an alkaline-earth metal. $$CaO + H_2O \rightarrow Ca(OH)_2$$, producing a strong base. So $$CaO$$ is basic.

6. $$P_4O_{10}$$
Phosphorus is a non-metal. $$P_4O_{10} + 6\,H_2O \rightarrow 4\,H_3PO_4$$. Hence $$P_4O_{10}$$ is acidic.

7. $$N_2O_3$$
Nitrogen is a non-metal, and the oxide reacts with water to give nitrous acid: $$N_2O_3 + H_2O \rightarrow 2\,HNO_2$$. Therefore $$N_2O_3$$ is acidic.

8. $$Li_2O$$
Lithium is an alkali metal. $$Li_2O + H_2O \rightarrow 2\,LiOH$$. Thus $$Li_2O$$ is basic.

9. $$MgO$$
Magnesium, an alkaline-earth metal, forms oxide that reacts with acids producing salt and water, so it is basic.

With all the classifications complete, we inspect every option to see whether the first oxide is acidic, the second one basic, and the third one amphoteric, exactly in that order.

Option A: $$Na_2O$$ (basic), $$SO_3$$ (acidic), $$Al_2O_3$$ (amphoteric) - the sequence is basic-acidic-amphoteric, not correct.

Option B: $$Cl_2O$$ (acidic), $$CaO$$ (basic), $$P_4O_{10}$$ (acidic) - the third oxide is not amphoteric, so the option is wrong.

Option C: $$N_2O_3$$ (acidic), $$Li_2O$$ (basic), $$Al_2O_3$$ (amphoteric). This exactly matches the required pattern acidic-basic-amphoteric.

Option D: $$MgO$$ (basic), $$Cl_2O$$ (acidic), $$Al_2O_3$$ (amphoteric) - again the order is basic-acidic-amphoteric, hence not correct.

Only Option C satisfies the given order.

Hence, the correct answer is Option C.