Select the most appropriate option to improve the underlined segment in the given sentence. If there is no need to improve it, select 'no improvement required'.
The first step in making a kite is to fasten two sticks of bamboo together in the form of a cross.
1
in making a kite is to be fastened
2
in making a kite is to fastening
3
into making a kite is fasten
4
no improvement required