Which of the following is the most stable?

Which one of the following is correct about the stability of the given ions?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{P}_4O_{10} + H_2O \longrightarrow H_3PO_4$

Who discovered the allotrope of carbon known as fullerene?

Assertion : Stannous chloride gives grey precipitate with mercuric chloride,but stannic chloride does not do so.
Reason : Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to metallic mercury.

Superphosphate of lime contains