Which of the following packet destination addresses will R2 forward to R1, according to this summary?

This question is about route summary.
Example of route summary calculation The routing table stores the following networks:
172.16.12.0/24
172.16.13.0/24
172.16.14.0/24
172.16.15.0/24

Routing protocols summarize or aggregate routes based on shared network numbers within the network. To calculate the summarized route of the router, it is necessary to determine how many bits on the left of those addresses are the same. The steps are shown below:
+ Step one: Convert addresses to binary format and align them.
+ Step two: Find out the identical last bit of all addresses.
+ Step three: Calculate how many bits are the same. The summarized route is an IP address with a slash, which will be helpful.

172.16.12.0/24= 172.16.000011 00.00000000
172.16.13.0/24= 172.16.000011 01.00000000
172.16.14.0/24= 172.16.000011 10.00000000
172.16.15.0/24= 172.16.000011 11.00000000
172.16.15.255/24= 172.16.000011 11.11111111

The first 22 bits of IP addresses 172.16.12.0—172.16.15.255 are identical, so the best summarized route is 172.16.12.0/22.
Using route summary can reduce the routing items on the summarized router to decrease the memory occupied and network traffic generated by routing protocol.
Route summary implementation:

The bits on the left of multiple addresses must be identical.
Routing protocol should select route according to the 32-bit IP address and the prefix length of the maximum 32 bit address.
Routing update must contain 32-bit IP address and the prefix length (subnet mask)