which strikeprice option to buy?

- very far out of the money, like 5-10 value = for thrill, not trading

- far out of money like 30-35 value = for aggressive betting on profit from earlier trades

- out of the money like 70-100 value = normal trade position

- in the money like 100-150 = when you are confident 

- deep in the money like 250-400 = alternate to buying futures

- deeper in the money = not much extra benefit though risk increases

Once the value of the option enters the next, higher level, you may skim the option to lower/earlier category and take some profit/money off the table.

Caution : Never put 5% (at worst 10%) of your trading capital in single trade.

except aggressive betting of profits of one trade. eg you turn 10 to 12 lac....and want to bet aggressively with that 2 lac profit, provided you have an evolved dependable tested plan. several traders have made big sums with that approach.