Find out number of reagents which can oxidise 
(i) I2/NaOH
(ii) KMnO4/H⊕
(iii) Tollen's reagent
(iv) LiAlH4
(v) NaBH4
(vii) SeO2/Δ
(viii) NH2 – NH2 / pH (4–6)
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The compound is an aldehyde group. Oxidizing agents convert aldehydes to carboxylic acids. Let's check each reagent:
(i) I₂/NaOH (Haloform reaction) oxidizes methyl ketones, not aldehydes. No.
(ii) KMnO₄/H⁺ is a strong oxidizer. Yes:
(iii) Tollen's reagent (Ag⁺) gives silver mirror test. Yes.
(iv) LiAlH₄ is a reducing agent (to alcohol). No.
(v) NaBH₄ is a reducing agent. No.
(vi) SeO₂ oxidizes methylene group adjacent to carbonyl, not the aldehyde itself. No.
(vii) NH₂-NH₂/pH is Wolff-Kishner reduction (to alkane). No.
Final Answer: 2 reagents (ii and iii)