Question says to find the correct function from the given choices for given graph. By looking at the graph we find that there are steps so it is clear that it is graph of floor function which is usually written as y=[x]
Graph of y=[x] pass throuh origin but given graph is above the origin so that means there must be some vertical shift.
Since given graph is above origin about 7 units so that indicates, there is 7 unit upward shift in the parent function y=[x]
Hence required function can be found by adding 7 to y=[x]
Hence final answer is y=[x]+7.
