Both equation I and II are balanced, but equation II is the correct way to write the balanced equation. Why do you think this is? (Hint: Think fractions.)
I) 2 SnO2 + 4 H2 → 2 Sn + 4 H2O
II) SnO2 + 2 H2 → Sn + 2 H2O

Because you have to give the simplest ratio of equation. Equation I can be simplified by dividing all the coefficients by 2 to make it into equation II.

*Every equation has to be in the simplest form of coefficients.

Ratio of Equation I :

2 : 4 : 2 : 4

Ratio of Equation II :

1 : 2 : 1 : 2

the answer is alpha particles hope i you