Answer:
b creating an air force
Step-by-step explanation:
Most powers giving to the congress are expressed powers because they are written in the constitution, but some powers are given to the congress which are not written in the constitution, known as implied powers.
Also elastic clause allow the congress to exercise power to meet new needs, for example the power to create an air force. This power is nor in the constitution but allow the congress to do as part of its expressed powers in supporting armies.