Answer:
Step-by-step explanation:
lets start from the expression
, first remember that
is a constant with no units, so we do not need to consider it for this problem, so lets just think about

Next lets replace the units, l is the length which is represented in metters by international units system
g is the gravitational constants, so the units are lengt divided by time squared, since time is in seconds we have

so pluging that into our formula we have

Now see we are dividing by a fraction, remember that to divide by a fraction is the same as to multiply by the reciprocal fraction, so we just flip the fraction and we get

then if we perform the multiplication we have inside the radical we get

Then since we are multiplying and dividing by m, the m's just cancel and we have

Now remember that square and square root are inverse operations, so they cancel each other and we are left with just
, which means seconds, so the answer would be option 5
hope that helps, good bye :)