Your are booting your system and found out that there are too many kernel and options are available for booting. Sometime just your /boot partition is just filled up with old kernels. You need to remove old kernels
Here in just a quick way we will remove unused old kernel from Linux systems.
Remove old kernels from CentOS/RedHat/Fedora
Install yum utils for automatic removal of kernels.
# yum install yum-utils
Check the installed kernels.
# rpm -q kernel kernel-tools-3.10.0-229.20.1.el7.x86_64 kernel-3.10.0-229.14.1.el7.x86_64 kernel-3.10.0-229.20.1.el7.x86_64 kernel-headers-3.10.0-229.20.1.el7.x86_64
Remove old kernels and keep only two kernels for safer side. Current and previous.
# package-cleanup --oldkernels --count=2
To make sure only two kernels installed or remain while updating the system. Update your /etc/yum.conf with following changes.