This checks a basic, well known 2014 Lok Sabha election fact.
335546: This is wrong. Reading it as 335 and 546, neither number matches the real seat totals.
334545: This is wrong. Reading it as 334 and 545, this is also off from the actual figures.
336543: This is correct. Reading it as 336 and 543, the BJP-led NDA alliance won 336 seats out of the 543 Lok Sabha seats declared in the 2014 general election, with the BJP alone crossing the majority mark on its own with 282 seats.
331544: This is wrong. Reading it as 331 and 544, both numbers are off, and the total Lok Sabha strength itself is 543, not 544.
The correct answer is C, 336543, which splits into 336 NDA seats out of 543 total.