This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to fix poor soil drainage
Identify where water collects.
Watch your yard during rainfall. Note exactly where water tends to pool and sit.

Available options:
(a). Also take into consideration how light or heavy the rainfall is, which may affect how large the affected area is. Plant stakes or flags in the center of the area and/or its borders while it's still wet if you think you will lose sight of it once it dries..
(b). Water forming in wet area can be a sign of poor drainage. Check your property's water indevelopment rates if it is directly in the ground and in a water source like a river or canal..
(c). Read damp pages or figures that indicate weather conditions before making a decision. Search landscape websites for many map publications on rainfall, or search the parks and gardens section of your state's national parks and gardens club..
(d). Run a compass or portable device over the ground to get a good idea of how rain is flowing from a crack in the ground, and seek a suitable water source. Natural sinkholes are well-known for the inward sloped soil they form..
The answer is:
(a).