Tax calculation on foreign freelance icome and salary

Hi, I have the following queries regarding calculation of tax on foreign freelance income and salary income.

1. Is foreign (US) freelance income generated in the months of January, February and March taxable in the same financial year in India? 
2. Can presumptive taxation scheme be opted if the sum of salary and freelancing income exceeds 50 lakhs but the freelancing income is less than 50 lakh.