Answer:
B
Explanation:
Line H is represented by the equation: 

And we want to find Line K such that the set of equations has infinitely many solutions. 
Remember the three solution sets for linear equations: 
- If the two are parallel, they have no solutions. 
- If the two are not parallel, they will intersect and thus have only one solution. 
- If the two are the exact same line, then they will have infinitely many solutions. 
From Line H, we can divide both sides by two. This yields the equivalent equation:

Therefore, the new equation and Line H are the same line. Thus, they will have infinitely many solutions. 
The answer is B.