Please explain why they're valid/invalid, thanks!

2. For the following variable declarations, int *x-pt; long *y_addr; long *dt_addr; long *pt_addr; double *pt_z; int a; long b; double c; determine which of the following statements is valid. (a) y-addr = &a; (b) y addr = a; (c) dt_addr = &a; (d) dt_addr = a; (e) pt z = &a; (f) pt_addr = a; (g) y addr = x-pt: (h) y addr = &b; (i) y-addr = b; 6) dt_addr = &b; (k) dt_addr = b; (1) pt_addr = &b; (m) pt_addr = b; (n) y addr = dt_addr; (o) y addr = &c; (P) y addr = c; (q) da_addr = &c; (1) dt_addr = c; (s) pt_addr = &c; (t) pt_addr = c; (u) y addr = pt_addr