Final answer:
The sum of 3 and 4 is 7. The correct answer to the question 'What's 3+4?' is option c) 7.
Step-by-step explanation:
The question presented, 'What's 3+4?', refers to a simple addition problem requiring the summation of the numbers 3 and 4. Basic arithmetic dictates that when 3 is added to 4, the sum equals 7. Therefore, the correct answer to '3+4' is indeed 7.
This solution aligns with the fundamental mathematical rule of addition:
3+4=7
In correspondence to the provided options, option c) 7 accurately represents the correct solution to the given addition problem. Hence, the correct choice among the options is c) 7.