Table:
J4 College Park–Bethesda MetroExtra line
System	Metrobus
Operator	Washington Metropolitan Area Transit Authority
Garage	Montgomery
Livery	MetroExtra
Status	In Service
Began service	April 15, 2002
Locale	Prince George's County, Montgomery County
Communities served	College Park, Maryland, University Of Maryland, Langley Park, Maryland, Takoma Park, Maryland, Silver Spring, Maryland, Rock Creek Forest, Chevy Chase, Maryland, Bethesda, Maryland
Landmarks served	College Park–University of Maryland station, University Of Maryland, Langley Park, Maryland, Takoma Park, Maryland, Takoma Langley Crossroads Transit Center, Silver Spring station, Rock Creek Forest, Chevy Chase, Maryland, Bethesda station
Start	College Park–University of Maryland station
Via	River Road, Paint Branch Parkway, Campus Drive, University Boulevard, New Hampshire Avenue, Piney Branch Road, Flower Avenue, Wayne Avenue, Colesville Road, East-West Highway
End	Bethesda station
Level	Weekday Peak Hour Service Only
Frequency	20 minutes
Operates	5:20 AM – 9:30 AM, 3:25 PM – 7:45 PM
Transfers	SmarTrip only

Examine the given table and identify the contents of cells located at specified locations, denoted by row and column indices. The value of every target cell should be presented in the JSON format of {"row_id":"m", "column_id":"n", "cell_value":"<Corresponding Cell Value>"}, e.g., {"row_id":"10", "column_id":"3", "cell_value":"District"}.
Specified positions:
the 5th row and the 2nd column
the 13th row and the 1st column
the 7th row and the 1st column
the 16th row and the 1st column
the 7th row and the 2nd column

The extracted cell contents are listed below.
{"row_id":"5", "column_id":"2", "cell_value":"MetroExtra"}
{"row_id":"13", "column_id":"1", "cell_value":"End"}
{"row_id":"7", "column_id":"1", "cell_value":"Began service"}
{"row_id":"16", "column_id":"1", "cell_value":"Operates"}
{"row_id":"7", "column_id":"2", "cell_value":"April 15, 2002"}