Theory:

“Rubbish!” said Dad..
“Now we’ll try Plan C.
Easy as winking;
To a climber like me!”
 
Then he climbed up high;
On the garden wall.
Guess what?
He did’t fall
Explanation:
 
Stanza \(9\) depicts the scene in which the child's father disregarded his wife's warnings and pleas and devised a new strategy (plan c), proclaiming himself to be a great climber once more. He also dismissed his wife's remarks, calling them "rubbish".
 
The tenth stanza indicates his third plan. He attempted to climb up the garden wall on his third attempt. He didn't collapse at the third effort, and he finally succeeded. He had scaled the garden wall in order to get closer to the tree.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Winking
It refers to something that can be done quickly, in a blink of an eye
2.
Ignore
To avoid or to not consider
Reference:
National Council of Educational Research and Training (2007). Honeycomb. Dad and cat and the tree - Kit Wright (pp.107-109). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.