Mark each of the following true or false. 

___ a. Q is a field of quotients of Z. 

___ b. R is a field of quotients of Z. 

___ c. R is a field of quotients of R 

___ d. C is a field of quotients of R. 

___ e. If D is a field, then any field of quotients of D is isomorphic to D. 

___ f. The fact that D has no divisors of 0 was used strongly several times in the construction of a field F of quotients of the integral domain D. 

___ g. Every element of an integral domain Dis a unit in a field F of quotients of D. 

___ h. Every nonzero element of an integral domain D is a unit in a field F of quotients of D. 

___ i. A field of quotients F' of a subdomain D' of an integral domain D can be regarded as a subfield of some field of quotients of D. 

___ j. Every field of quotients of Z is isomorphic to Q.