Solution

We calculate protein and fat for each option.

Option $1$: $200$ grams of $B$ and $200$ grams of $C$

Protein $=10%$ of $200+20%$ of $200$

$=20+40=60$ grams

Fat $=30%$ of $200+10%$ of $200$

$=60+20=80$ grams

Option $2$: $150$ grams of $A$ and $200$ grams of $B$

Protein $=20%$ of $150+10%$ of $200$

$=30+20=50$ grams

Fat $=40%$ of $150+30%$ of $200$

$=60+60=120$ grams

Option $3$: $350$ grams of $C$

Protein $=20%$ of $350$

$=70$ grams

Fat $=10%$ of $350$

$=35$ grams

Option $4$: $100$ grams of $A$ and $250$ grams of $C$

Protein $=20%$ of $100+20%$ of $250$

$=20+50=70$ grams

Fat $=40%$ of $100+10%$ of $250$

$=40+25=65$ grams

Options $3$ and $4$ give the highest protein, that is $70$ grams.

But option $3$ has lower fat.

Therefore, Ranveer should choose $350$ grams of $C$.